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Sample records for beaufort sea

  1. Gray whale sightings in the Canadian Beaufort Sea, September 2014

    Science.gov (United States)

    Iwahara, Yuka; Fujiwara, Amane; Ito, Keizo; Miyashita, Kazushi; Mitani, Yoko

    2016-06-01

    Gray whales (Eschrichtius robustus) are distributed within the productive neritic and estuarine waters of the North Pacific Ocean, the Bering Sea, and adjacent waters of the Arctic Ocean. They migrate to high-latitude feeding grounds each spring. Their main feeding grounds in the Arctic include the Chirikov Basin, the northeastern Chukchi Sea from Pt. Hope to Cape Lisburne and Pt. Lay to Pt. Barrow, and the northwestern Chukchi Sea along the Chukotka coast. Although sightings are rare in the Canadian Beaufort Sea, we observed three gray whales in two groups in this area in September 2014. A mud plume was observed near one of the whales, suggesting the animal had been feeding. In the Alaskan Beaufort Sea, large-scale monitoring of the distributions of marine mammals has been continuously conducted since 1979; however, there has been less monitoring in the Canadian Beaufort Sea. Therefore, it is necessary to record opportunistic sightings, such as those described here.

  2. Climate change and ice hazards in the Beaufort Sea

    OpenAIRE

    Barber, D. G.; McCullough, G.; Babb, D.; Komarov, A.S.; L. M. Candlish; Lukovich, J.V.; Asplin, M.; S. Prinsenberg; Dmitrenko, I.; S. Rysgaard

    2014-01-01

    Abstract Recent reductions in the summer extent of sea ice have focused the world’s attention on the effects of climate change. Increased CO2-derived global warming is rapidly shrinking the Arctic multi-year ice pack. This shift in ice regimes allows for increasing development opportunities for large oil and gas deposits known to occur throughout the Arctic. Here we show that hazardous ice features remain a threat to stationary and mobile infrastructure in the southern Beaufort Sea. With the ...

  3. Ice Draft and Ice Velocity Data in the Beaufort Sea, 1990-2003

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set provides measurement of sea ice draft (m) and the movement of sea ice (cm/s) over the continental shelf of the Eastern Beaufort Sea. The data set...

  4. Polar bear maternity denning in the Beaufort Sea

    Science.gov (United States)

    Amstrup, S.; Gardner, C.

    1994-01-01

    The distribution of polar bears (Ursus maritimus) is circumpolar in the NOrthern Hemisphere, but known locations of maternal dens are concentrated in relatively few, widely scattered locations. Denning is either uncommon or unknown within gaps. To understand effects of industrial development and propose increases in hunting, the temporal and spatial distribution of denning in the Beaufort Sea must be known. We caputred and radiocollared polar bears between 1981 and 1991 and determined tht denning in the Beaufort Sea region was sufficient to account for the estimated population there. Of 90 dend, 48 were on drifting pack ice, 38 on land, and 4 on land-fast ice. The portions of dens on land was higher (P= 0.029) in later compared with earlier years of the study. Bears denning on pack ice drifting as far as 997 km (x=385km) while in dens. there was no difference in cun production by bears denning on land and pack ice (P =0.66). Mean entry and exit dates were 11 November and 5 April for land dens and 22 November and 26 March for pack-ice dens. Female polar bears captured in the Beaufort Sea appeared to be isolated from those caught eat of Cape Bathurst in Canada. Of 35 polar bears that denned along the mainland coast of Alaska and Canada 80% denned between 137 00'W snf 146 59'W. Bears followed to >1 den did not reuse sites and consecutive dens were 20-1,304 km apart. However radio-collared bears are largely faithful to substrate (pack-ice, land, and land-fast ice) and the general geographic area of previous dens. Bears denning on land may be vunerable to human activities such as hunting and industrial development. However, predictable denning chronology and alck of site fidelity indicate that many potential impacts on denning polar bears could be mitigated.

  5. Recurring Spring Leads and Landfast Ice in the Beaufort and Chukchi Seas, 1993-2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In the Beaufort and Chukchi Seas, the most significant sea ice anomalies have occurred in the summer ice extent (Eicken et al. 2006). In addition, there has been a...

  6. Biophysical research requirements for Beaufort Sea hydrocarbon development

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-08-15

    This review identified biophysical research requirements and data gaps for the development of hydrocarbon resources in the Beaufort Sea. The potential major effects of critical activities during each phase of the offshore oil and gas development cycle were identified in order to assess the impacts on local communities and traditional harvesting methods. Baseline environmental conditions were established. Information needs were ranked using 3 criteria: (1) the current understanding of the biophysical component in terms of present status and long-term sustainability, (2) the potential impact of the oil and gas development on the long-term sustainability of the biophysical component, and (3) the timeline for completion of the research relative to the expected development for the Beaufort Sea region. Mitigation and environmental management plans were outlined, and key research, data collection, and data analyses required to address data gaps were identified. Previous gap analyses for the region were reviewed. Data from a series of workshops conducted with various stakeholders were also included in the study. High research priorities include the assessment of the effects of climatic change on the physical oceanography of the region, studies on deepwater plankton, benthos, and fish. It was concluded that studies are needed to determine the effects of development on marine mammals, avifauna, and macroalgae. 207 refs., 49 tabs., 4 figs.

  7. Effects of Mackenzie River Discharge and Bathymetry on Sea Ice in the Beaufort Sea

    Science.gov (United States)

    Nghiem, S. V.; Hall, D. K.; Rigor, I. G; Li, P.; Neumann, G.

    2014-01-01

    Mackenzie River discharge and bathymetry effects on sea ice in the Beaufort Sea are examined in 2012 when Arctic sea ice extent hit a record low. Satellite-derived sea surface temperature revealed warmer waters closer to river mouths. By 5 July 2012, Mackenzie warm waters occupied most of an open water area about 316,000 sq km. Surface temperature in a common open water area increased by 6.5 C between 14 June and 5 July 2012, before and after the river waters broke through a recurrent landfast ice barrier formed over the shallow seafloor offshore the Mackenzie Delta. In 2012, melting by warm river waters was especially effective when the strong Beaufort Gyre fragmented sea ice into unconsolidated floes. The Mackenzie and other large rivers can transport an enormous amount of heat across immense continental watersheds into the Arctic Ocean, constituting a stark contrast to the Antarctic that has no such rivers to affect sea ice.

  8. Monitoring Beaufort Sea waterfowl and marine birds. Final report

    International Nuclear Information System (INIS)

    The purpose of the project was to design and implement a monitoring protocol for marine waterbirds in the Jones-Return Islands area of the central Alaska Beaufort Sea. Because of its overwhelming and widespread abundance, relatively sedentary behavior, ease in counting, and the extensive historical database, the oldsquaw duck (Clangula hyemalis) was selected as the focal species for the study. Two null hypotheses were formulated concerning potential changes in the numbers and distribution of oldsquaws in relation to OCS development in the industrial area, compared to a control area (Stockton-Maguire-Flaxman Islands area) located about 50 km to the east. A 9-year historical database (1977 through 1984, and 1989) was analyzed using multivariate techniques to determine which of several predictor variables recorded during past aerial surveys significantly influenced oldsquaw density in the central Alaska Beaufort Sea. Separate analyses were conducted for the complete open-water period, and for the molt period of oldsquaws, when they are flightless and relatively sedentary in the study areas. The results of the two multiple regression analyses indicated that only about 57% and 68%, respectively, of the total amount of variation in oldsquaw density during the two periods could be explained by predictor variables recorded during aerial surveys. Candidate predictor variables were year of study, day of year, time of day, wind speed and direction, habitat, east-west position (study area) of the transect, distance of the transect from a barrier island, water depth beneath the transect, wave height and amount of ice recorded on the transect. Predictor variables associated with habitat, day of the year, time of day of the survey, amount of ice, and wave height recorded on transect during the survey had the most significant effect on oldsquaw density

  9. Scaling observations of surface waves in the Beaufort Sea

    Directory of Open Access Journals (Sweden)

    Madison Smith

    2016-04-01

    Full Text Available Abstract The rapidly changing Arctic sea ice cover affects surface wave growth across all scales. Here, in situ measurements of waves, observed from freely-drifting buoys during the 2014 open water season, are interpreted using open water distances determined from satellite ice products and wind forcing time series measured in situ with the buoys. A significant portion of the wave observations were found to be limited by open water distance (fetch when the wind duration was sufficient for the conditions to be considered stationary. The scaling of wave energy and frequency with open water distance demonstrated the indirect effects of ice cover on regional wave evolution. Waves in partial ice cover could be similarly categorized as distance-limited by applying the same open water scaling to determine an ‘effective fetch’. The process of local wave generation in ice appeared to be a strong function of the ice concentration, wherein the ice cover severely reduces the effective fetch. The wave field in the Beaufort Sea is thus a function of the sea ice both locally, where wave growth primarily occurs in the open water between floes, and regionally, where the ice edge may provide a more classic fetch limitation. Observations of waves in recent years may be indicative of an emerging trend in the Arctic Ocean, where we will observe increasing wave energy with decreasing sea ice extent.

  10. On coherent ice drift features in the southern Beaufort sea

    Science.gov (United States)

    Lukovich, J. V.; Bélanger, C.; Barber, D. G.; Gratton, Y.

    2014-10-01

    Previous studies have highlighted reversals in the Beaufort Gyre on regional scales during summer months, and more recently, throughout the annual cycle. In this study we investigate coherent ice drift features associated with individual ice beacons during winter 2008 that may be a signature of ice-coast interactions, atmospheric and/or oceanic forcing. Examined in particular are three case studies associated with reversals in ice beacon trajectories in January and April of 2008; case I corresponds to a meander reversal event in January, case II to a loop reversal event in April, and case III to a meander reversal event located to the northeast of the Mackenzie Canyon in April. An assessment of atmospheric and oceanic conditions during these reversal events shows enhanced ocean-sea-ice-atmosphere dynamical coupling during the Case I meander reversal event in January and comparatively weak coupling during the Case II loop and Case III meander reversal event in April. Absolute (single-particle/beacon) and relative (two-particle/beacon) dispersion results demonstrate dominant meridional ice drift displacement and inter-beacon separation for Case I relative to Cases II and III indicative of ice-ice and ice-coast interactions in January. The results from this investigation provide an ice drift case study analysis relevant to, and template for, high-resolution sea ice dynamic modeling studies essential for safety and hazard assessments of transportation routes and shipping lanes, ice forecasting, and nutrient and contaminant transport by sea ice in the Arctic.

  11. Role of ice dynamics in anomalous ice conditions in the Beaufort Sea during 2006 and 2007

    Science.gov (United States)

    Hutchings, J. K.; Rigor, I. G.

    2012-05-01

    A new record minimum in summer sea ice extent was set in 2007 and an unusual polynya formed in the Beaufort Sea ice cover during the summer of 2006. Using a combination of visual observations from cruises, ice drift, and satellite passive microwave sea ice concentration, we show that ice dynamics during preceding years included events that preconditioned the Beaufort ice pack for the unusual patterns of opening observed in both summers. Intrusions of first year ice from the Chukchi Sea to the Northern Beaufort, and increased pole-ward ice transport from the western Arctic during summer has led to reduced replenishment of multiyear ice, older than five years, in the western Beaufort, resulting in a younger, thinner ice pack in most of the Beaufort. We find ice younger than five years melts out completely by the end of summer, south of 76N. The 2006 unusual polynya was bounded to the south by an ice tongue composed of sea ice older than 5 years, and formed when first year and second year ice melted between 76N and the older ice to the south. In this paper we demonstrate that a recent shift in ice circulation patterns in the western Arctic preconditions the Beaufort ice pack for increased seasonal ice zone extent.

  12. Observations and modeling of the ice-ocean conditions in the coastal Chukchi and Beaufort Seas

    Institute of Scientific and Technical Information of China (English)

    JIN Meibing; WANG Jia; MIZOBATA Kohei; HU Haoguo; SHIMADA Koji

    2008-01-01

    The Chukchi and Beaufort Seas include several important hydrological features: inflow of the Pacific water, Alaska coast current (ACC), the seasonal to perennial sea ice cover, and landfast ice along the Alaskan coast. The dynamics of this coupled ice-ocean sys-tem is important for both regional scale oceanography and large-scale global climate change research. A number of moorings were de-ployed in the area by JAMSTEC since 1992, and the data revealed highly variable characteristics of the hydrological environment. A re-gional high-resolution coupled ice-ocean model of the Chukchi and Beaufort Seas was established to simulate the ice-ocean environment and unique seasonal landfast ice in the coastal Beaufort Sea. The model results reproduced the Beaufort gyre and the ACC. The depth-averaged annual mean ocean currents along the Beaufort Sea coast and shelf break compared well with data from four moored ADCPs, but the simulated velocity had smaller standard deviations, which indicate small-scale eddies were frequent in the region. The model re-suits captured the seasonal variations of sea ice area as compared with remote sensing data, and the simulated sea ice velocity showed an almost stationary area along the Beaufort Sea coast that was similar to the observed landfast ice extent. It is the combined effects of the weak oceanic current near the coast, a prevailing wind with an onshore component, the opposite direction of the ocean current, and the blocking by the coastline that make the Beaufort Sea coastal areas prone to the formation of landfast ice.

  13. Spatial and temporal variability of sea-surface temperature fronts in the coastal Beaufort Sea

    Science.gov (United States)

    Mustapha, Sélima Ben; Larouche, Pierre; Dubois, Jean-Marie

    2016-08-01

    An analysis of 11 years of sea surface temperatures images allowed the determination of the frontal occurrence probability in the southeastern Beaufort Sea using the single-image edge detection method. Results showed that, as the season progresses, fronts become more detectable due to solar heating of the surface layer. Some recurrent features can be identified in the summer time frontal climatology such as the Mackenzie River plume front, the Cape Bathurst front, the Mackenzie Trough front and the Amundsen Gulf front. These areas may be playing an important role in the biological processes acting as drivers to local enhanced biological productivity.

  14. On the characteristics of sea ice divergence/convergence in the Southern Beaufort Sea

    Directory of Open Access Journals (Sweden)

    J. V. Lukovich

    2014-07-01

    Full Text Available An understanding of spatial gradients in sea ice motion, or deformation, is essential to understanding of ocean-sea-ice-atmosphere interactions and realistic representations of sea ice in models used for the purposes of prediction. This is particularly true for the southern Beaufort Sea, where significant offshore hydrocarbon resource development increases the risk of oil and other contaminants dispersing into the marginal ice zone. In this study, sea ice deformation is examined through evaluation of ice beacon triplets from September to November 2009 in the southern Beaufort Sea (SBS, defined according to distance from the coastline on deployment. Results from this analysis illustrate that ice beacon triplets in the SBS demonstrate spatiotemporal differences in their evolution at the periphery and interior of the ice pack. The time rate of change in triplet area highlights two intervals of enhanced divergence and convergence in fall, 2009. Investigation of sea ice and atmospheric conditions during these intervals shows that until mid-September, all triplets respond to northerly flow, while during the second interval of enhanced divergence/convergence in October only one triplet responds to persistent northeasterly flow due to its proximity to the ice edge, in contrast to triplets located at the interior of the pack. Differences in sea ice deformation and dispersion near the pack ice edge and interior are further demonstrated in the behavior of triplets B and C in late October/early November. The results from this analysis highlight differences in dispersion and deformation characteristics based on triplet proximity to the southernmost ice edge and coastline, with implications for modeling studies pertaining to sea ice dynamics and dispersion.

  15. Beaufort Sea planning area oil and gas Lease Sale 170. Final environmental impact statement

    International Nuclear Information System (INIS)

    This environmental impact statement (EIS) assesses Lease Sale 170 proposed for August 1998 and comprised of 363 lease blocks in the Beaufort Sea planning area. The analysis addresses the significant environmental and socioeconomic concerns identified in the scoping process. Scoping consisted of input from State and Federal agencies, the petroleum industry, Native groups, environmental and public interest groups, and concerned individuals. The potential effects expected from the interaction between environmental resources and OCS-related activities were determined with respect to available scientific information and traditional knowledge. This EIS incorporates information from the Final EIS for the Beaufort Sea OCS Sale 144 (USD01, MMS, 1996a)

  16. Mud Volcanoes from the Beaufort Sea to the South China Sea

    Science.gov (United States)

    Lundsten, E. M.; Paull, C. K.; Caress, D. W.; Dallimore, S.; Melling, H.; Liu, C. S.; Anderson, K.; Gwiazda, R.

    2015-12-01

    The detailed morphology of five submarine mud volcanoes were surveyed using an Autonomous Underwater Vehicle (AUV) developed at the Monterey Bay Aquarium Research Institute. Mud volcanoes are constructional features built by extrusion of gas, subsurface fluids and fine-grained sediment. Two surveys covering four submarine mud volcanoes were conducted on the CCGS Sir Wilfred Laurier in the Beaufort Sea in the Canadian Arctic. A survey of one mud volcano was conducted on the Taiwanese Ocean Research V in the South China Sea, SE of Taiwan. The AUV carried a multibeam sonar, a 1-6 kHz chirp sub-bottom profiler, and a110 kHz sidescan, and obtained overlapping multibeam bathymetric coverage at a vertical resolution of 0.15 m with a horizontal footprint of 0.9 m and chirp seismic-reflection profiles with a vertical resolution of 0.11 m. Mud volcanoes were either flat topped or conical. The conical mud volcano off Taiwan had a diameter of ~2 km and 10° side slopes; the conical feature in the Beaufort Sea had a diameter of ~1.5 km and 4° side slopes. The sides of the conical mud volcanoes were smooth, suggesting they were formed by sediment flows that emanate from a vent on their crests. The flanks of the conical mud volcanoes characteristically had very low acoustic reflectivity, but one single high reflectivity trail from the crest of the Beaufort Sea mud volcano indicates a recent flow. Three mud volcanoes in the Beaufort Sea formed circular, flat-topped plateaus that are up to ~1.1 km in diameter and elevated up to 30 m from the surrounding seafloor. The fine scale morphology and reflectivity on these plateaus show low relief, concentric, and ovoid circles that appear to be mud boils probably associated with eruptive events of varying ages at shifting vent sites. The different mud volcano shapes are attributed to variations in the viscosity of the erupting sediment slurries and may represent a sequential morphology, which is altered by shifts in venting position over

  17. Polar bear population dynamics in the southern Beaufort Sea during a period of sea ice decline.

    Science.gov (United States)

    Bromaghin, Jeffrey F; Mcdonald, Trent L; Stirling, Ian; Derocher, Andrew E; Richardson, Evan S; Regehr, Eric V; Douglas, David C; Durner, George M; Atwood, Todd; Amstrup, Steven C

    2015-04-01

    In the southern Beaufort Sea of the United States and Canada, prior investigations have linked declines in summer sea ice to reduced physical condition, growth, and survival of polar bears (Ursus maritimus). Combined with projections of population decline due to continued climate warming and the ensuing loss of sea ice habitat, those findings contributed to the 2008 decision to list the species as threatened under the U.S. Endangered Species Act. Here, we used mark-recapture models to investigate the population dynamics of polar bears in the southern Beaufort Sea from 2001 to 2010, years during which the spatial and temporal extent of summer sea ice generally declined. Low survival from 2004 through 2006 led to a 25-50% decline in abundance. We hypothesize that low survival during this period resulted from (1) unfavorable ice conditions that limited access to prey during multiple seasons; and possibly, (2) low prey abundance. For reasons that are not clear, survival of adults and cubs began to improve in 2007 and abundance was comparatively stable from 2008 to 2010, with ~900 bears in 2010 (90% CI 606-1212). However, survival of subadult bears declined throughout the entire period. Reduced spatial and temporal availability of sea ice is expected to increasingly force population dynamics of polar bears as the climate continues to warm. However, in the short term, our findings suggest that factors other than sea ice can influence survival. A refined understanding of the ecological mechanisms underlying polar bear population dynamics is necessary to improve projections of their future status and facilitate development of management strategies. PMID:26214910

  18. Bowhead whale body condition and links to summer sea ice and upwelling in the Beaufort Sea

    Science.gov (United States)

    George, John C.; Druckenmiller, Matthew L.; Laidre, Kristin L.; Suydam, Robert; Person, Brian

    2015-08-01

    We examined the response of bowhead whale (Balaena mysticetus) body condition to summer sea ice conditions and upwelling-favorable winds. We used a long-term dataset collected from whales of the Bering-Chukchi-Beaufort Seas (BCB) stock to estimate various body condition indices (BCI's) for individual whales that were harvested by Alaskan Eskimos. A series of offshore regions frequented by bowhead whales in summer were delineated and used to quantify interannual summertime environmental conditions including: (a) mean open water fraction, (b) duration of melt season, (c) date of continuous freeze-up, and (d) mean upwelling-favorable wind stress. Body condition was analyzed relative to these metrics for both the preceding summer feeding season and the previous three seasons combined. Our analysis indicates a significant increase in the long-term trend in an axillary girth-based body condition index (BCIG) over the study period (1989-2011). The increase in BCIG is likely associated with the trend in overall reduction of sea ice, including increased duration of open water, changes in upwelling potential (wind stress), and possibly higher primary production in the Pacific Arctic marine ecosystem favoring water-column invertebrates. We found strong significant positive correlations between BCIG and late summer open water fraction in the Beaufort Sea and smaller nearshore areas off the Mackenzie Delta and west of Banks Island. Additionally, BCIG was positively and significantly correlated with duration of melt season, later date of freeze-up in the Beaufort Sea, and upwelling-favorable winds on the Mackenzie shelf and west of Banks Island. A strong seasonal difference in BCI's was noted for subadult bowheads, presumably associated with summer feeding; however, yearlings were found to drop in BCI over at least the first summer after weaning. Our results indicate an overall increase in bowhead whale body condition and a positive correlation with summer sea ice loss over the

  19. Fish communities across a spectrum of habitats in the western Beaufort Sea and Chukchi Sea

    Science.gov (United States)

    Logerwell, E.; Busby, M.; Carothers, C.; Cotton, S.; Duffy-Anderson, J.; Farley, E.; Goddard, P.; Heintz, R.; Holladay, B.; Horne, J.; Johnson, S.; Lauth, B.; Moulton, L.; Neff, D.; Norcross, B.; Parker-Stetter, S.; Seigle, J.; Sformo, T.

    2015-08-01

    The increased scientific interest in the Arctic due to climate change and potential oil and gas development has resulted in numerous surveys of Arctic marine fish communities since the mid-2000s. Surveys have been conducted in nearly all Arctic marine fish habitats: from lagoons, beaches and across the continental shelf and slope. This provides an opportunity only recently available to study Arctic fish communities across a spectrum of habitats. We examined fish survey data from lagoon, beach, nearshore benthic, shelf pelagic and shelf benthic habitats in the western Beaufort Sea and Chukchi Sea. Specifically, we compare and contrast relative fish abundance and length (a proxy for age) among habitats and seas. We also examined ichthyoplankton presence/absence and abundance of dominant taxa in the shelf habitat. Our synthesis revealed more similarities than differences between the two seas. For example, our results show that the nearshore habitat is utilized by forage fish across age classes, and is also a nursery area for other species. Our results also indicated that some species may be expanding their range to the north, for example, Chinook Salmon. In addition, we documented the presence of commercially important taxa such as Walleye Pollock and flatfishes (Pleuronectidae). Our synthesis of information on relative abundance and age allowed us to propose detailed conceptual models for the life history distribution of key gadids in Arctic food webs: Arctic and Saffron Cod. Finally, we identify research gaps, such as the need for surveys of the surface waters of the Beaufort Sea, surveys of the lagoons of the Chukchi Sea, and winter season surveys in all areas. We recommend field studies on fish life history that sample multiple age classes in multiple habitats throughout the year to confirm, resolve and interpret the patterns in fish habitat use that we observed.

  20. 75 FR 18404 - Safety Zone; FRONTIER DISCOVERER, Outer Continental Shelf Drillship, Chukchi and Beaufort Sea...

    Science.gov (United States)

    2010-04-12

    ... Continental Shelf Drillship, Chukchi and Beaufort Sea, Alaska'' in the Federal Register (75 FR 803). The NPRM... discussion of the background and purpose for this rule can be found in the preamble to the NPRM (75 FR 803... vessel located at the coordinates listed in Table 1. These coordinates are based upon [NAD 83] UTM Zone...

  1. Microsatellite DNA and mitochondrial DNA variation in polar bears (Ursus maritimus) from the Beaufort and Chukchi seas, Alaska

    Science.gov (United States)

    Cronin, M.A.; Amstrup, Steven C.; Scribner, K.T.

    2006-01-01

    Radiotelemetry data have shown that polar bears (Ursus maritimus Phipps, 1774) occur in separate subpopulations in the Chukchi Sea and the southern Beaufort Sea. However, segregation is not absolute, and there is overlap of ranges of animals in each subpopulation. We used genetic variation at eight microsatellite DNA loci and mitochondrial DNA (mtDNA) to further assess the degree of spatial structure of polar bears from the Chukchi and southern Beaufort seas. Microsatellite allele frequencies and mtDNA haplotype frequencies of bears from the southern Beaufort and Chukchi seas did not differ significantly. Lack of differentiation at both maternally inherited mtDNA and bi-parentally inherited microsatellite loci suggests that gene flow between the two areas is mediated by both sexes. The genetic data indicate that polar bears in the southern Beaufort and Chukchi seas compose one interbreeding population. However, there is considerable fidelity to ranges in each area, particularly by adult females. The combined genetic and movement data suggest that polar bears could be managed as Beaufort Sea and Chukchi Sea subpopulations of a combined southern Beaufort Sea and Chukchi Sea population. ?? 2006 NRC.

  2. Survival and breeding of polar bears in the southern Beaufort Sea in relation to sea ice.

    Science.gov (United States)

    Regehr, Eric V; Hunter, Christine M; Caswell, Hal; Amstrup, Steven C; Stirling, Ian

    2010-01-01

    1. Observed and predicted declines in Arctic sea ice have raised concerns about marine mammals. In May 2008, the US Fish and Wildlife Service listed polar bears (Ursus maritimus) - one of the most ice-dependent marine mammals - as threatened under the US Endangered Species Act. 2. We evaluated the effects of sea ice conditions on vital rates (survival and breeding probabilities) for polar bears in the southern Beaufort Sea. Although sea ice declines in this and other regions of the polar basin have been among the greatest in the Arctic, to date population-level effects of sea ice loss on polar bears have only been identified in western Hudson Bay, near the southern limit of the species' range. 3. We estimated vital rates using multistate capture-recapture models that classified individuals by sex, age and reproductive category. We used multimodel inference to evaluate a range of statistical models, all of which were structurally based on the polar bear life cycle. We estimated parameters by model averaging, and developed a parametric bootstrap procedure to quantify parameter uncertainty. 4. In the most supported models, polar bear survival declined with an increasing number of days per year that waters over the continental shelf were ice free. In 2001-2003, the ice-free period was relatively short (mean 101 days) and adult female survival was high (0.96-0.99, depending on reproductive state). In 2004 and 2005, the ice-free period was longer (mean 135 days) and adult female survival was low (0.73-0.79, depending on reproductive state). Breeding rates and cub litter survival also declined with increasing duration of the ice-free period. Confidence intervals on vital rate estimates were wide. 5. The effects of sea ice loss on polar bears in the southern Beaufort Sea may apply to polar bear populations in other portions of the polar basin that have similar sea ice dynamics and have experienced similar, or more severe, sea ice declines. Our findings therefore are

  3. Survival and breeding of polar bears in the southern Beaufort Sea in relation to sea ice

    Science.gov (United States)

    Regehr, E.V.; Hunter, C.M.; Caswell, H.; Amstrup, Steven C.; Stirling, I.

    2010-01-01

    1. Observed and predicted declines in Arctic sea ice have raised concerns about marine mammals. In May 2008, the US Fish and Wildlife Service listed polar bears (Ursus maritimus) - one of the most ice-dependent marine mammals - as threatened under the US Endangered Species Act. 2. We evaluated the effects of sea ice conditions on vital rates (survival and breeding probabilities) for polar bears in the southern Beaufort Sea. Although sea ice declines in this and other regions of the polar basin have been among the greatest in the Arctic, to date population-level effects of sea ice loss on polar bears have only been identified in western Hudson Bay, near the southern limit of the species' range. 3. We estimated vital rates using multistate capture-recapture models that classified individuals by sex, age and reproductive category. We used multimodel inference to evaluate a range of statistical models, all of which were structurally based on the polar bear life cycle. We estimated parameters by model averaging, and developed a parametric bootstrap procedure to quantify parameter uncertainty. 4. In the most supported models, polar bear survival declined with an increasing number of days per year that waters over the continental shelf were ice free. In 2001-2003, the ice-free period was relatively short (mean 101 days) and adult female survival was high (0 ∙ 96-0 ∙ 99, depending on reproductive state). In 2004 and 2005, the ice-free period was longer (mean 135 days) and adult female survival was low (0 ∙ 73-0 ∙ 79, depending on reproductive state). Breeding rates and cub litter survival also declined with increasing duration of the ice-free period. Confidence intervals on vital rate estimates were wide. 5. The effects of sea ice loss on polar bears in the southern Beaufort Sea may apply to polar bear populations in other portions of the polar basin that have similar sea ice dynamics and have experienced similar, or more severe, sea ice declines. Our findings

  4. AFSC/NMML: Passive acoustic sonobuoy recordings from Bering, Chukchi, and Beaufort Seas in Alaska, 2007-2014

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Marine Mammal Laboratory (NMML) has conducted passive acoustic monitoring in the Bering, Chukchi, and Western Beaufort Seas to determine...

  5. SBI AWS02-I CTD Data collected from the Polar Star in the Beaufort and Chukchi Seas (NODC Accession 0001290)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The field phase of the Shelf-Basin Interactions Experiment (SBI) began in 2002 with a series of three cruises to the Chukchi and Beaufort Seas. SBI is a...

  6. Emerging trends in the sea state of the Beaufort and Chukchi seas

    Science.gov (United States)

    Thomson, Jim; Fan, Yalin; Stammerjohn, Sharon; Stopa, Justin; Rogers, W. Erick; Girard-Ardhuin, Fanny; Ardhuin, Fabrice; Shen, Hayley; Perrie, Will; Shen, Hui; Ackley, Steve; Babanin, Alex; Liu, Qingxiang; Guest, Peter; Maksym, Ted; Wadhams, Peter; Fairall, Chris; Persson, Ola; Doble, Martin; Graber, Hans; Lund, Bjoern; Squire, Vernon; Gemmrich, Johannes; Lehner, Susanne; Holt, Benjamin; Meylan, Mike; Brozena, John; Bidlot, Jean-Raymond

    2016-09-01

    The sea state of the Beaufort and Chukchi seas is controlled by the wind forcing and the amount of ice-free water available to generate surface waves. Clear trends in the annual duration of the open water season and in the extent of the seasonal sea ice minimum suggest that the sea state should be increasing, independent of changes in the wind forcing. Wave model hindcasts from four selected years spanning recent conditions are consistent with this expectation. In particular, larger waves are more common in years with less summer sea ice and/or a longer open water season, and peak wave periods are generally longer. The increase in wave energy may affect both the coastal zones and the remaining summer ice pack, as well as delay the autumn ice-edge advance. However, trends in the amount of wave energy impinging on the ice-edge are inconclusive, and the associated processes, especially in the autumn period of new ice formation, have yet to be well-described by in situ observations. There is an implicit trend and evidence for increasing wave energy along the coast of northern Alaska, and this coastal signal is corroborated by satellite altimeter estimates of wave energy.

  7. Recent observations of intraspecific predation and cannibalism among polar bears in the southern Beaufort Sea

    Science.gov (United States)

    Amstrup, Steven C.; Stirling, I.; Smith, T.S.; Perham, C.; Thiemann, G.W.

    2006-01-01

    Intraspecific killing has been reported among polar bears (Ursus maritimus), brown bears (U. arctos), and black bears (U. americanus). Although cannibalism is one motivation for such killings, the ecological factors mediating such events are poorly understood. Between 24 January and 10 April 2004, we confirmed three instances of intraspecific predation and cannibalism in the Beaufort Sea. One of these, the first of this type ever reported for polar bears, was a parturient female killed at her maternal den. The predating bear was hunting in a known maternal denning area and apparently discovered the den by scent. A second predation event involved an adult female and cub recently emerged from their den, and the third involved a yearling male. During 24 years of research on polar bears in the southern Beaufort Sea region of northern Alaska and 34 years in northwestern Canada, we have not seen other incidents of polar bears stalking, killing, and eating other polar bears. We hypothesize that nutritional stresses related to the longer ice-free seasons that have occurred in the Beaufort Sea in recent years may have led to the cannibalism incidents we observed in 2004. ?? Springer-Verlag 2006.

  8. Observed sea ice thickness changes in the Beaufort Gyre through synthesis of Eulerian and Lagrangian data

    Science.gov (United States)

    Mahoney, A. R.; Hutchings, J. K.; Haas, C.; Eicken, H.

    2014-12-01

    In-situ and satellite observations have shown significant reductions in the extent and thickness of Arctic sea ice, which are considered by many to be evidence of major cryospheric changes amplifying global climate change. Multiyear (MY) sea ice thinning and retreat of the oldest and thickest ice, will accelerate further ice loss. MY sea ice also represents the greatest impediment to navigation in the Arctic and greatest hazard to marine infrastructure. Recirculation of sea ice within the Beaufort Gyre is critical to the replenishment of MY ice lost from the Arctic through either melt or export. Here we analyze thickness changes of sea ice as it drifts in different regions of the Gyre. Using a combined Eulerian-Lagrangian approach we identify satellite-tracked buoys that made repeat overpasses within 30 km of four moored ice profiling sonars (IPSs), which comprise part of the Beaufort Gyre Exploration Program (BGEP). Using the IPS data, we derive ice draft distributions corresponding to each of these overpasses, which allows tracking of changes in the ice thickness in vicinity of each buoy. Changes in modal values of ice thickness during winter agree with simple models of thermodynamic growth.In the case of one buoy that made a total of four overpasses (see figure below), a dramatic shift in a secondary modal thickness during the summer of 2007 agrees well the magnitude of melt recorded by a nearby ice mass balance buoy (IMB). To extend the number of repeat passes, we generate pseudo-Langrangian ice drift tracks using daily gridded fields of satellite-derived ice velocity. This allows us to deploy "numerical buoys" every day anywhere in the Arctic. Using this approach we identify numerous cases where sea ice observed over one mooring persistently drifts over another. Such inter-mooring ice advection events allow us to examine how sea ice thickness distribution in the Beaufort Gyre is influenced by dynamic and thermodynamic processes processes.

  9. Sediment transport by sea ice in the Chukchi and Beaufort Seas: Increasing importance due to changing ice conditions?

    Science.gov (United States)

    Eicken, H.; Gradinger, R.; Gaylord, A.; Mahoney, A.; Rigor, I.; Melling, H.

    2005-12-01

    Sediment-laden sea ice is widespread over the shallow, wide Siberian Arctic shelves, with off-shelf export from the Laptev and East Siberian Seas contributing substantially to the Arctic Ocean's sediment budget. By contrast, the North American shelves, owing to their narrow width and greater water depths, have not been deemed as important for basin-wide sediment transport by sea ice. Observations over the Chukchi and Beaufort shelves in 2001/02 revealed the widespread occurrence of sediment-laden ice over an area of more than 100,000 km 2 between 68 and 74°N and 155 and 170°W. Ice stratigraphic studies indicate that sediment inclusions were associated with entrainment of frazil ice into deformed, multiple layers of rafted nilas, indicative of a flaw-lead environment adjacent to the landfast ice of the Chukchi and Beaufort Seas. This is corroborated by buoy trajectories and satellite imagery indicating entrainment in a coastal polynya in the eastern Chukchi Sea in February of 2002 as well as formation of sediment-laden ice along the Beaufort Sea coast as far eastward as the Mackenzie shelf. Moored upward-looking sonar on the Mackenzie shelf provides further insight into the ice growth and deformation regime governing sediment entrainment. Analysis of Radarsat Synthetic Aperture (SAR) imagery in conjunction with bathymetric data help constrain the water depth of sediment resuspension and subsequent ice entrainment (>20 m for the Chukchi Sea). Sediment loads averaged at 128 t km -2, with sediment occurring in layers of roughly 0.5 m thickness, mostly in the lower ice layers. The total amount of sediment transported by sea ice (mostly out of the narrow zone between the landfast ice edge and waters too deep for resuspension and entrainment) is at minimum 4×10 6 t in the sampling area and is estimated at 5-8×10 6 t over the entire Chukchi and Beaufort shelves in 2001/02, representing a significant term in the sediment budget of the western Arctic Ocean. Recent

  10. Submarine slope failures in the Beaufort Sea; Influence of gas hydrate decomposition

    Science.gov (United States)

    Grozic, J. L.; Dallimore, S.

    2012-12-01

    The continental shelf of the Beaufort Sea is composed of complex of marine and non-marine sequences of clay, silt, and sand. In many areas of the shelf these sediments contain occurrences of ice-bonded permafrost and associated pressure and temperature conditions that are conducive to the occurrence of methane gas hydrates. This complex environment is undergoing dramatic warming, where changes in sea level, ocean bottom temperatures, and geothermal regimes are inducing permafrost thawing and gas hydrate decomposition. Decomposition is inferred to be occurring at the base and top of the gas hydrate stability zone, which will cause sediment weakening and the generation of excess water and free gas. In such settings, the overlying permafrost cap may act as a permeability barrier, which could result in significant excess pore pressures and reduction in sediment stability. The shelf to slope transition is thought to be an area of extensive regional instability with acoustic records indicating there is upwards of 500 km of slumps and glides extending over the entire Beaufort margin. Some of these slide regions are coincident with up-dip limit of the permafrost gas hydrate stability zone. In this paper, a two dimensional model of the Beaufort shelf was constructed to examine the influence of gas hydrate decomposition on slope stability. The model relies on available data on the Beaufort sediments generated from offshore hydrocarbon exploration in the 1980s and 90s, as well as knowledge available from multidisciplinary marine research programs conducted in the outer shelf area. The slope stability model investigates the influence of marine transgression and ocean bottom warming by coupling soil deformation with hydrate dissociation during undrained conditions. By combining mechanical and thermal loading of the sediment, a more accurate indication of slope stability was obtained. The stability analysis results indicate a relatively low factor of safety for the Beaufort

  11. Climate change and ice hazards in the Beaufort Sea

    DEFF Research Database (Denmark)

    Barber, D. G.; McCullough, G.; Babb, D.;

    2014-01-01

    Recent reductions in the summer extent of sea ice have focused the world’s attention on the effects of climate change. Increased CO2-derived global warming is rapidly shrinking the Arctic multi-year ice pack. This shift in ice regimes allows for increasing development opportunities for large oil ...

  12. Scaling observations of surface waves in the Beaufort Sea

    OpenAIRE

    Madison Smith; Jim Thomson

    2016-01-01

    Abstract The rapidly changing Arctic sea ice cover affects surface wave growth across all scales. Here, in situ measurements of waves, observed from freely-drifting buoys during the 2014 open water season, are interpreted using open water distances determined from satellite ice products and wind forcing time series measured in situ with the buoys. A significant portion of the wave observations were found to be limited by open water distance (fetch) when the wind duration was sufficient for th...

  13. Minimum distribution of subsea ice-bearing permafrost on the US Beaufort Sea continental shelf

    Science.gov (United States)

    Brothers, Laura L.; Hart, Patrick E.; Ruppel, Carolyn D.

    2012-01-01

    Starting in Late Pleistocene time (~19 ka), sea level rise inundated coastal zones worldwide. On some parts of the present-day circum-Arctic continental shelf, this led to flooding and thawing of formerly subaerial permafrost and probable dissociation of associated gas hydrates. Relict permafrost has never been systematically mapped along the 700-km-long U.S. Beaufort Sea continental shelf and is often assumed to extend to ~120 m water depth, the approximate amount of sea level rise since the Late Pleistocene. Here, 5,000 km of multichannel seismic (MCS) data acquired between 1977 and 1992 were examined for high-velocity (>2.3 km s−1) refractions consistent with ice-bearing, coarse-grained sediments. Permafrost refractions were identified along permafrost, which does not extend seaward of 30 km offshore or beyond the 20 m isobath.

  14. Organohalogen concentrations in blood and adipose tissue of Southern Beaufort Sea polar bears

    Science.gov (United States)

    Bentzen, T.W.; Muir, D.C.G.; Amstrup, Steven C.; O'Hara, T. M.

    2008-01-01

    We analyzed 151 organohalogen chemicals (OHCs) in whole blood and subcutaneous fat of 57 polar bears sampled along the Alaskan Beaufort Sea coast in spring, 2003. All major organochlorine pesticides, PCBs, PBDEs and their congeners were assessed. Concentrations of most OHCs continue to be lower among Southern Beaufort Sea polar bears than reported for other populations. Additionally, toxaphenes and related compounds were assessed in adipose tissue, and 8 perflourinated compounds (PFCs) were examined in blood. Perfluorooctane sulfonate (PFOS) concentrations exceeded those of any other contaminant measured in blood. ??Chlordane concentrations were higher in females, and both ??PCBs and ??Chlordane concentrations in adipose tissue decreased significantly with age. The rank order of OHC mean concentrations; ??PCB > ??10PCB > PCB153 > ??Chlordane > Oxychlordane > PCB180 > ??HCH > ??-HCH > ??DDT > p,p-DDE > ??PBDE > HCB > Toxaphene was similar for compounds above detection limits in both fat and blood. Although correlation between OHC concentrations in blood and adipose tissue was examined, the predictability of concentrations in one matrix for the other was limited. ?? 2008 Elsevier B.V.

  15. Bird dispersal and deterrent techniques for oil spills in the Beaufort Sea

    International Nuclear Information System (INIS)

    A review is presented of techniques that are most likely to be effective for dispersing and deterring birds in the event of an oil spill in the Canadian Beaufort Sea. The evaluation considered the species of birds present, behaviour and mobility of the birds, logistics considerations, and the proven or likely effectiveness of the techniques. The deterrants were evaluated for effectiveness in different habitats including sedge lowlands in the Mackenzie Delta during autumn, seabird colonies, bays and lagoons in summer, sea ice and leads during spring, and offshore during open-water periods. The techniques evaluated included full size and radio-controlled aircraft, boats, shooting and pyrotechnics, gas cannons and exploders, other sound-based deterrents, vision-based deterrents, hawks and falcons, physical barriers, lure areas, trapping, chemical aversion agents, and high energy electromagnetic waves. The most universally applicable method of bird dispersal is hazing by aircraft. Universal methods of bird deterrance are gas cannons, shotguns, shellcrackers, rockets and mortars

  16. 75 FR 13654 - Use of Foreign-Flag Anchor Handling Vessels in the Beaufort Sea or Chukchi Sea Adjacent to Alaska

    Science.gov (United States)

    2010-03-22

    ... Maritime Administration Use of Foreign-Flag Anchor Handling Vessels in the Beaufort Sea or Chukchi Sea...-flag anchor handling vessels in certain cases (and for a limited period of time) if no U.S.-flag... the Maritime Administration determines that U.S.- flag vessels are not suitable and ]...

  17. 76 FR 79764 - Use of Foreign-Flag Anchor Handling Vessels in the Beaufort Sea or Chukchi Sea Adjacent to Alaska

    Science.gov (United States)

    2011-12-22

    ... Maritime Administration Use of Foreign-Flag Anchor Handling Vessels in the Beaufort Sea or Chukchi Sea...-flag anchor handling vessels in certain cases (and for a limited period of time) if no U.S.-flag... the Maritime Administration determines that U.S.- flag vessels are not suitable and...

  18. Ice effects on a barge-based oil spill response system in the Alaskan Beaufort Sea

    Energy Technology Data Exchange (ETDEWEB)

    Bronson, M.; Thompson, E. [BP Exploration Alaska Inc., Anchorage, AK (United States); McAdams, F.; McHale, J. [Alaska Clean Seas, Prudhoe Bay, AK (United States)

    2002-07-01

    In 1999 Alaska Clean Seas assembled a marine oils spill response task force at Prudhoe Bay in preparation for potential oil well blowout in the Beaufort Sea, especially in pack ice conditions. The effects of pack ice on response efforts was measured in timed trials in the nearshore Beaufort Sea. A spill containment and recovery barge-based system reached its oil spill response operating limit in the thick ice of spring and in the thin ice of autumn at concentrations below 1/10. When the boom sweep encountered ice with 1/10 or more coverage, the ice became concentrated in the boom apex and isolated the skimmers. If thick ice pieces were longer than 7 meters, they lifted the boom, and rolled under it. Smaller pieces were able to either move through the apex, or accumulate in the boom. Ice breakers were able to manage the ice in their path by reducing thick drift ice concentrations from 3/10 and 5/10 down to less than 1/10. Barge-based booms were also able to direct ice pieces down the boom length to the boom apex. A pair of steel grates along the hull of the barge protected the floating LORI side brush skimmers from ice damage. A 5 per cent down time was experienced in a continuous 12 hour test in pack ice due to interference from drift ice. The total average down time was 12 per cent of the test period. Barges could move through the ice at break-up in July. By fall freeze-up, slush ice would accumulate, but it did not obstruct the weir skimmer pumps and hoses, not did it interfere with the skimmer's brushes. 8 refs., 5 tabs., 4 figs.

  19. Field measurement of local ice pressures on the ARAON in the Beaufort Sea

    Directory of Open Access Journals (Sweden)

    Lee Tak-Kee

    2014-12-01

    Full Text Available This study conducted four field measurements of local ice pressure during the icebreaking voyage of the icebreaking research vessel “ARAON” in the Chukchi and Beaufort seas from July to August of 2010. For measurements, 14 strain gauges, including 8 strain gauge rosettes, were set on the bow of the port side. Influence coefficients were determined using a finite element model of the instrumented area and they were used to convert the measured strains on the hull structure to local ice pressures. The converted maximum pressure was calculated as 2.12 MPa on an area of 0.28 m2. Pressure-area curves were developed from the surveyed pressure data and the results were compared with previously measured data. The study results are expected to provide an understanding of local ice pressures and thus be useful in the structural design of ice class ships.

  20. Bowhead whale behavior in relation to seismic exploration, Alaskan Beaufort Sea, Autumn 1981. Study report (Final)

    Energy Technology Data Exchange (ETDEWEB)

    Fraker, M.A.; Ljungblad, D.K.; Richardson, W.J.; Van Schoik, D.R.

    1985-10-01

    Behavior of bowhead whales (Balsena mysticetus) in the eastern part of the Alaskan Beaufort Sea or near the Alaska/Yukon border was observed from a circling turbine-powered Goose aircraft on 10 dates from 12 September to 5 October 1981. On three of these dates, the whales were exposed t, noise impulses from seismic vessels 13 km or more away. Some behavioral data were acquired. In both the presence and the absence of seismic impulses, most bowheads appeared to be feeding in the water column, although slow travel and active socializing were sometimes detected. Sonobuoys detected bowhead calls both in the presence and the absence of seismic impulses. There was no clear evidence of unusual behavior in the presence of seismic impulses.

  1. Active mud volcanoes on the continental slope of the Canadian Beaufort Sea

    Science.gov (United States)

    Paull, C. K.; Dallimore, S. R.; Caress, D. W.; Gwiazda, R.; Melling, H.; Riedel, M.; Jin, Y. K.; Hong, J. K.; Kim, Y.-G.; Graves, D.; Sherman, A.; Lundsten, E.; Anderson, K.; Lundsten, L.; Villinger, H.; Kopf, A.; Johnson, S. B.; Hughes Clarke, J.; Blasco, S.; Conway, K.; Neelands, P.; Thomas, H.; Côté, M.

    2015-09-01

    Morphologic features, 600-1100 m across and elevated up to 30 m above the surrounding seafloor, interpreted to be mud volcanoes were investigated on the continental slope in the Beaufort Sea in the Canadian Arctic. Sediment cores, detailed mapping with an autonomous underwater vehicle, and exploration with a remotely operated vehicle show that these are young and actively forming features experiencing ongoing eruptions. Biogenic methane and low-chloride, sodium-bicarbonate-rich waters are extruded with warm sediment that accumulates to form cones and low-relief circular plateaus. The chemical and isotopic compositions of the ascending water indicate that a mixture of meteoric water, seawater, and water from clay dehydration has played a significant role in the evolution of these fluids. The venting methane supports extensive siboglinid tubeworms communities and forms some gas hydrates within the near seafloor. We believe that these are the first documented living chemosynthetic biological communities in the continental slope of the western Arctic Ocean.

  2. Polar bears in the Beaufort Sea: A 30-year mark-recapture case history

    Science.gov (United States)

    Amstrup, Steven C.; McDonald, T.L.; Stirling, I.

    2001-01-01

    Knowledge of population size and trend is necessary to manage anthropogenic risks to polar bears (Ursus maritimus). Despite capturing over 1,025 females between 1967 and 1998, previously calculated estimates of the size of the southern Beaufort Sea (SBS) population have been unreliable. We improved estimates of numbers of polar bears by modeling heterogeneity in capture probability with covariates. Important covariates referred to the year of the study, age of the bear, capture effort, and geographic location. Our choice of best approximating model was based on the inverse relationship between variance in parameter estimates and likelihood of the fit and suggested a growth from ~500 to over 1,000 females during this study. The mean coefficient of variation on estimates for the last decade of the study was 0.16-the smallest yet derived. A similar model selection approach is recommended for other projects where a best model is not identified by likelihood criteria alone.

  3. Migratory bird use of the coastal lagoon system of the Beaufort Sea coastline within the Arctic National Wildlife Refuge, Alaska, 1983

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report covers the migratory bird use of the coastal lagoon system of the Beaufort Sea coastline within the Arctic National Wildlife Refuge, Alaska. Aerial...

  4. ANWR progress report number FY84-6: Movement of molting oldsquaws within the Beaufort Sea coastal lagoons of Arctic National Wildlife Refuge, Alaska, 1983

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report covers the movement of molting oldsquaw within the Beaufort Sea Coastal lagoons of the Arctic National Wildlife Refuge, Alaska. During August, 1983, 16...

  5. SBI AWS02-I Bottle and Nutrient Data collected from the Polar Star in the Beaufort and Chukchi Seas (NODC Accession 0001288)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The field phase of the Shelf-Basin Interactions Experiment (SBI) began in 2002 with a series of three cruises to the Chukchi and Beaufort Seas. SBI is a...

  6. Prediction of oil spill occurrence probabilities in the Alaskan Beaufort and Chukchi Seas OCS

    International Nuclear Information System (INIS)

    Estimates of oil spill occurrences are used by the Minerals Management Service (MMS) Alaska OCS Region for the development of environmental impact statements for hypothetical offshore development scenarios resulting from the sale of leases for the United States Beaufort and Chukchi Sea Outer Continental Shelf. Although estimates of expected values of oil spill probabilities and sizes provide a simple basis for estimating environmental impacts, the magnitude and distribution of uncertainties can alter the significance of these expected values. In order to develop the probability distributions of oil spill occurrences, this paper presented a study that used non-Arctic empirical data together with their variance as a starting point. In addition, Arctic effect distributions and their impact on both the original data variance as well as additional unique Arctic effect distributions such as those for ice gouging and scour were integrated. In addition, an oil spill occurrence model based on fault tree methodology was developed and evaluated using Monte Carlo methods with all significant inputs in distributed form in order to provide the expected values and their variability. The study involved the quantification of four principal spill occurrence indicator probability distributions, including annual spill frequency; annual spill frequency per barrel produced; spill index, which refers to the product of spill size and spill frequency; and life of field averages of the above indicators. The paper summarized the methodology and presented the results of its application to the estimation of oil spill probabilities and their characteristics for the Chukchi and Beaufort Seas region for typical future offshore development scenarios. It was recommended that the use of the Monte Carlo spill occurrence indicator model should be continued for new scenarios to support MMS needs, as it is the best model available for estimating spill occurrence. 12 refs., 2 tabs., 12 figs

  7. Age and sex composition of seals killed by polar bears in the eastern Beaufort Sea.

    Directory of Open Access Journals (Sweden)

    Nicholas W Pilfold

    Full Text Available BACKGROUND: Polar bears (Ursus maritimus of the Beaufort Sea enter hyperphagia in spring and gain fat reserves to survive periods of low prey availability. We collected information on seals killed by polar bears (n=650 and hunting attempts on ringed seal (Pusa hispida lairs (n=1396 observed from a helicopter during polar bear mark-recapture studies in the eastern Beaufort Sea in spring in 1985-2011. We investigated how temporal shifts in ringed seal reproduction affect kill composition and the intraspecific vulnerabilities of ringed seals to polar bear predation. PRINCIPAL FINDINGS: Polar bears primarily preyed on ringed seals (90.2% while bearded seals (Erignathus barbatus only comprised 9.8% of the kills, but 33% of the biomass. Adults comprised 43.6% (150/344 of the ringed seals killed, while their pups comprised 38.4% (132/344. Juvenile ringed seals were killed at the lowest proportion, comprising 18.0% (62/344 of the ringed seal kills. The proportion of ringed seal pups was highest between 2007-2011, in association with high ringed seal productivity. Half of the adult ringed seal kills were ≥ 21 years (60/121, and kill rates of adults increased following the peak of parturition. Determination of sex from DNA revealed that polar bears killed adult male and adult female ringed seals equally (0.50, n=78. The number of hunting attempts at ringed seal subnivean lair sites was positively correlated with the number of pup kills (r(2 =0.30, P=0.04, but was not correlated with the number of adult kills (P=0.37. CONCLUSIONS/SIGNIFICANCE: Results are consistent with decadal trends in ringed seal productivity, with low numbers of pups killed by polar bears in spring in years of low pup productivity, and conversely when pup productivity was high. Vulnerability of adult ringed seals to predation increased in relation to reproductive activities and age, but not gender.

  8. Linking mercury exposure to habitat and feeding behaviour in Beaufort Sea beluga whales

    Science.gov (United States)

    Loseto, L. L.; Stern, G. A.; Deibel, D.; Connelly, T. L.; Prokopowicz, A.; Lean, D. R. S.; Fortier, L.; Ferguson, S. H.

    2008-12-01

    Mercury (Hg) levels in the Beaufort Sea beluga population have been increasing since the 1990's. Ultimately, it is the Hg content of prey that determines beluga Hg levels. However, the Beaufort Sea beluga diet is not understood, and little is known about the diet Hg sources in their summer habitat. During the summer, they segregate into social groups based on habitat use leading to the hypothesis that they may feed in different food webs explaining Hg dietary sources. Methyl mercury (MeHg) and total mercury (THg) levels were measured in the estuarine-shelf, Amundsen Gulf and epibenthic food webs in the western Canadian Arctic collected during the Canadian Arctic Shelf Exchange Study (CASES) to assess their dietary Hg contribution. To our knowledge, this is the first study to report MeHg levels in estuarine fish and epibenthic invertebrates from the Arctic Ocean. Although the Mackenzie River is a large source of Hg, the estuarine-shelf prey items had the lowest MeHg levels, ranging from 0.1 to 0.27 μg/g dry weight (dw) in arctic cisco ( Coregonus autumnalis) and saffron cod ( Eleginus gracilis) respectively. Highest MeHg levels occurred in fourhorn sculpin ( Myoxocephalus quadricornis) (0.5 μg/g dw) from the epibenthic food web. Beluga hypothesized to feed in the epibenthic and Amundsen Gulf food webs had the highest Hg levels matching with high Hg levels in associated food webs, and estuarine-shelf belugas had the lowest Hg levels (2.6 μg/g dw), corresponding with the low food web Hg levels, supporting the variation in dietary Hg uptake. The trophic level transfer of Hg was similar among the food webs, highlighting the importance of Hg sources at the bottom of the food web as well as food web length. We propose that future biomagnification studies incorporate predator behaviour with food web structure to assist in the evaluation of dietary Hg sources.

  9. Sounds and vibrations in the frozen Beaufort Sea during gravel island construction.

    Science.gov (United States)

    Greene, Charles R; Blackwell, Susanna B; McLennan, Miles Wm

    2008-02-01

    Underwater and airborne sounds and ice-borne vibrations were recorded from sea-ice near an artificial gravel island during its initial construction in the Beaufort Sea near Prudhoe Bay, Alaska. Such measurements are needed for characterizing the properties of island construction sounds to assess their possible impacts on wildlife. Recordings were made in February-May 2000 when BP Exploration (Alaska) began constructing Northstar Island about 5 km offshore, at 12 m depth. Activities recorded included ice augering, pumping sea water to flood the ice and build an ice road, a bulldozer plowing snow, a Ditchwitch cutting ice, trucks hauling gravel over an ice road to the island site, a backhoe trenching the sea bottom for a pipeline, and both vibratory and impact sheet pile driving. For all but one sound source (underwater measurements of pumping) the strongest one-third octave band was under 300 Hz. Vibratory and impact pile driving created the strongest sounds. Received levels of sound and vibration, as measured in the strongest one-third octave band for different construction activities, reached median background levels <7.5 km away for underwater sounds, <3 km away for airborne sounds, and <10 km away for in-ice vibrations. PMID:18247873

  10. Fall Freeze-up of Sea Ice in the Beaufort-Chukchi Seas Using ERS-1 SAR and Buoy Data

    Science.gov (United States)

    Holt, B.; Winebrenner, B.; D., Nelson E.

    1993-01-01

    The lowering of air temperatures below freezing in the fall indicates the end of summer melt and the onset of steady sea ice growth. The thickness and condition of ice that remains at the end of summer has ramifications for the thickness that that ice will attain at the end of the following winter. This period also designates a shifting of key fluxes from upper ocean freshening from ice melt to increased salinity from brine extraction during ice growth. This transitional period has been examined in the Beaufort and Chukchi Seas using ERS-1 SAR imagery and air temperatures from drifting buoys during 1991 and 1992. The SAR imagery is used to examine the condition and types of ice present in this period. Much of the surface melt water has drained off at this time. Air temperatures from drifting buoys coincident in time and within 100 km radius of the SAR imagery have been obtained...

  11. Polar bears in the southern Beaufort Sea II: Demography and population growth in relation to sea ice conditions

    Science.gov (United States)

    Hunter, Christine M.; Caswell, Hal; Runge, Michael C.; Regehr, Eric V.; Amstrup, Steven C.; Stirling, Ian

    2007-01-01

    This is a demographic analysis of the southern Beaufort (SB) polar bear population. The analysis uses a female-dominant stage-classified matrix population model in which individuals are classified by age and breeding status. Parameters were estimated from capture-recapture data collected between 2001 and 2006. We focused on measures of long-term population growth rate and on projections of population size over the next 100 years. We obtained these results from both deterministic and stochastic demographic models. Demographic results were related to a measure of sea ice condition, ice(t), defined as the number of ice-free days, in year t, in the region of preferred polar bear habitat. Larger values of ice correspond to lower availability of sea ice and longer ice-free periods. Uncertainty in results was quantified using a parametric bootstrap approach that includes both sampling uncertainty and model selection uncertainty.

  12. Polar bear population status in the northern Beaufort Sea, Canada, 1971-2006

    Science.gov (United States)

    Stirling, I.; McDonald, T.L.; Richardson, E.S.; Regehr, E.V.; Amstrup, Steven C.

    2011-01-01

    Polar bears (Ursus maritimus) of the northern Beaufort Sea (NB) population occur on the perimeter of the polar basin adjacent to the northwestern islands of the Canadian Arctic Archipelago. Sea ice converges on the islands through most of the year. We used open-population capture–recapture models to estimate population size and vital rates of polar bears between 1971 and 2006 to: (1) assess relationships between survival, sex and age, and time period; (2) evaluate the long-term importance of sea ice quality and availability in relation to climate warming; and (3) note future management and conservation concerns. The highest-ranking models suggested that survival of polar bears varied by age class and with changes in the sea ice habitat. Model-averaged estimates of survival (which include harvest mortality) for senescent adults ranged from 0.37 to 0.62, from 0.22 to 0.68 for cubs of the year (COY) and yearlings, and from 0.77 to 0.92 for 2–4 year-olds and adults. Horvtiz-Thompson (HT) estimates of population size were not significantly different among the decades of our study. The population size estimated for the 2000s was 980 ± 155 (mean and 95% CI). These estimates apply primarily to that segment of the NB population residing west and south of Banks Island. The NB polar bear population appears to have been stable or possibly increasing slightly during the period of our study. This suggests that ice conditions have remained suitable and similar for feeding in summer and fall during most years and that the traditional and legal Inuvialuit harvest has not exceeded sustainable levels. However, the amount of ice remaining in the study area at the end of summer, and the proportion that continues to lie over the biologically productive continental shelf (polar bear population in the northern Beaufort Sea will eventually decline. Management and conservation practices for polar bears in relation to both aboriginal harvesting and offshore industrial activity will need

  13. Primary productivity and export fluxes on the Canadian shelf of the Beaufort Sea: A modelling study

    Science.gov (United States)

    Lavoie, Diane; Macdonald, Robie W.; Denman, Kenneth L.

    2009-01-01

    We present a coupled sea ice-ocean-biological (including ice algae) model in the Arctic Ocean. The 1D model was developed and implemented on the Canadian Beaufort Sea shelf to examine the importance of different physical processes in controlling the timing and magnitude of primary production and biogenic particle export over an annual cycle (1987). Our results show that the snow and sea ice cover melt and/or break-up controls the timing of the phytoplankton bloom but primary producers (ice algae and phytoplankton) on the outer shelf are essentially nutrient limited. The total annual primary production (22.7 to 27.7 g-C m - 2 ) is thus controlled by nutrient "pre-conditioning" in the previous fall and winter and by the depth of wind mixing that is controlled in part by the supply of fresh water at the end of spring (ice melt or runoff). The spring bloom represents about 40% of the total annual primary production and occurs in a period of the year when sampling is often lacking. Time interpolation of observed values to obtain total annual primary production, as done in many studies, was shown to lead to an underestimation of the actual production. Our simulated ratios of export to primary production vary between 0.42 and 0.44.

  14. Trophic transfer of persistent organochlorine contaminants (OCs) within an Arctic marine food web from the southern Beaufort-Chukchi Seas

    Energy Technology Data Exchange (ETDEWEB)

    Hoekstra, P.F.; O' Hara, T.M.; Fisk, A.T.; Borgaa, K.; Solomon, K.R.; Muir, D.C.G

    2003-08-01

    The trophic status and biomagnification of persistent OCs within the near-shore Beaufort-Chukchi Seas food web from Barrow, AK is discussed. - Stable isotope values ({delta}{sup 13}C, {delta}{sup 15}N) and concentrations of persistent organochlorine contaminants (OCs) were determined to evaluate the near-shore marine trophic status of biota and biomagnification of OCs from the southern Beaufort-Chukchi Seas (1999-2000) near Barrow, AK. The biota examined included zooplankton (Calanus spp.), fish species such as arctic cod (Boreogadus saida), arctic char (Salvelinus alpinus), pink salmon (Oncorhynchus gorbuscha), and fourhorn sculpin (Myoxocephalus quadricornis), along with marine mammals, including bowhead whales (Balaena mysticetus), beluga whales (Delphinapterus leucas), ringed seals (Phoca hispida) and bearded seals (Erignathus barbatus). The isotopically derived trophic position of biota from the Beaufort-Chukchi Seas marine food web, avian fauna excluded, is similar to other coastal food webs in the Arctic. Concentrations of OCs in marine mammals were significantly greater than in fish and corresponded with determined trophic level. In general, OCs with the greatest food web magnification factors (FWMFs) were those either formed due to biotransformation (e.g. p,p'-DDE, oxychlordane) or considered recalcitrant (e.g. {beta}-HCH, 2,4,5-Cl substituted PCBs) in most biota, whereas concentrations of OCs that are considered to be readily eliminated (e.g. {gamma}-HCH) did not correlate with trophic level. Differences in physical-chemical properties of OCs, feeding strategy and possible biotransformation were reflected in the variable biomagnification between fish and marine mammals. The FWMFs in the Beaufort-Chukchi Seas region were consistent with reported values in the Canadian Arctic and temperate food webs, but were statistically different than FWMFs from the Barents and White Seas, indicating that the spatial variability of OC contamination in top

  15. Trophic transfer of persistent organochlorine contaminants (OCs) within an Arctic marine food web from the southern Beaufort-Chukchi Seas

    International Nuclear Information System (INIS)

    The trophic status and biomagnification of persistent OCs within the near-shore Beaufort-Chukchi Seas food web from Barrow, AK is discussed. - Stable isotope values (δ13C, δ15N) and concentrations of persistent organochlorine contaminants (OCs) were determined to evaluate the near-shore marine trophic status of biota and biomagnification of OCs from the southern Beaufort-Chukchi Seas (1999-2000) near Barrow, AK. The biota examined included zooplankton (Calanus spp.), fish species such as arctic cod (Boreogadus saida), arctic char (Salvelinus alpinus), pink salmon (Oncorhynchus gorbuscha), and fourhorn sculpin (Myoxocephalus quadricornis), along with marine mammals, including bowhead whales (Balaena mysticetus), beluga whales (Delphinapterus leucas), ringed seals (Phoca hispida) and bearded seals (Erignathus barbatus). The isotopically derived trophic position of biota from the Beaufort-Chukchi Seas marine food web, avian fauna excluded, is similar to other coastal food webs in the Arctic. Concentrations of OCs in marine mammals were significantly greater than in fish and corresponded with determined trophic level. In general, OCs with the greatest food web magnification factors (FWMFs) were those either formed due to biotransformation (e.g. p,p'-DDE, oxychlordane) or considered recalcitrant (e.g. β-HCH, 2,4,5-Cl substituted PCBs) in most biota, whereas concentrations of OCs that are considered to be readily eliminated (e.g. γ-HCH) did not correlate with trophic level. Differences in physical-chemical properties of OCs, feeding strategy and possible biotransformation were reflected in the variable biomagnification between fish and marine mammals. The FWMFs in the Beaufort-Chukchi Seas region were consistent with reported values in the Canadian Arctic and temperate food webs, but were statistically different than FWMFs from the Barents and White Seas, indicating that the spatial variability of OC contamination in top-level marine Arctic predators is attributed to

  16. Marine ichthyoplankton data from the Canadian Beaufort Sea Shelf, July and September 1984

    Energy Technology Data Exchange (ETDEWEB)

    Chiperzak, D.B.; Hopky, G.E.; Lawrence, M.J.; Lacho, G.

    1990-02-01

    As part of the Beaufort Shelf Fish Habitat Research Subproject of the Northern Oil and Gas Action Program, ichthyoplankton were collected from 760 {mu}m Wiscosin net and 500 {mu}m neuston net plankton tows in July and September of 1984 along the Canadian Beaufort Sea Shelf. A total of 1408 larval fish representing six families and nine species groups were caught in the 34 plankton tows. Arctic cod (Boreogadus saida) was the most abundant larval fish species caught both in the Wisconsin and neuston tows. Standard length, total length, and wet-weight measurements were made on 1123 larval fish of which 1097 were Arctic cod. The July mean standard length for Arctic cod was 13.4 mm with a standard deviation of 2.7 mm, and a mean weight of 0.015 g with a standard deviation of 0.010 g. In September, Arctic cod mean standard length was 26.3 mm, standard deviation of 3.8 mm, and the mean weight was 0.130 g with a standard deviation of 0.058 g. A total of 126 fish were analyzed for stomach contents of which four were found to be empty. Copepods were the most frequently occurring food item in all four species groups analysed with Calanoida being the most frequently occurring and the most abundant food item for both B. saida and the fourhorn sculpin, Myoxcephalus quadricornis. Nine stomachs, all from B. saida, contained the parasite (Trematoda: Hemiuridae). 10 refs., 2 figs., 25 tabs.

  17. Upper Ocean Evolution Across the Beaufort Sea Marginal Ice Zone from Autonomous Gliders

    Science.gov (United States)

    Lee, Craig; Rainville, Luc; Perry, Mary Jane

    2016-04-01

    The observed reduction of Arctic summertime sea ice extent and expansion of the marginal ice zone (MIZ) have profound impacts on the balance of processes controlling sea ice evolution, including the introduction of several positive feedback mechanisms that may act to accelerate melting. Examples of such feedbacks include increased upper ocean warming though absorption of solar radiation, elevated internal wave energy and mixing that may entrain heat stored in subsurface watermasses (e.g., the relatively warm Pacific Summer (PSW) and Atlantic (AW) waters), and elevated surface wave energy that acts to deform and fracture sea ice. Spatial and temporal variability in ice properties and open water fraction impact these processes. To investigate how upper ocean structure varies with changing ice cover, and how the balance of processes shift as a function of ice fraction and distance from open water, four long-endurance autonomous Seagliders occupied sections that extended from open water, through the marginal ice zone, deep into the pack during summer 2014 in the Beaufort Sea. Sections reveal strong fronts where cold, ice-covered waters meet waters that have been exposed to solar warming, and O(10 km) scale eddies near the ice edge. In the pack, Pacific Summer Water and a deep chlorophyll maximum form distinct layers at roughly 60 m and 80 m, respectively, which become increasingly diffuse as they progress through the MIZ and into open water. The isopynal layer between 1023 and 1024 kgm‑3, just above the PSW, consistently thickens near the ice edge, likely due to mixing or energetic vertical exchange associated with strong lateral gradients in this region. This presentation will discuss the upper ocean variability, its relationship to sea ice extent, and evolution over the summer to the start of freeze up.

  18. Overview of field operations during a 2013 research expedition to the southern Beaufort Sea on the RV Araon

    OpenAIRE

    Jin, Y. K.; Riedel, Michael; Hong, J. K.; Nam, S. I.; Jung, J.Y.; Ha, S. Y.; Lee, J.Y.; Kim, G. Y.; Yoo, J.; Kim, H S; Kim, G.; Conway , K; Standen, G.; Ulmi, M.; Schreker, M.

    2015-01-01

    Research experiments conducted and preliminary findings The Expedition ARA04C is a multidisciplinary research program in the Beaufort Sea, carried out in collaboration between the Korea Polar Research Institute (KOPRI), Geological Survey of Canada (GSC), Department of Fisheries and Ocean (DFO), Monterey Bay Aquarium Research Institute (MBARI), and the Alfred Wegener Institute (AWI). The Expedition ARA04C on the IBRV Araon took place from September 6 to September 24, 2013 (Figure 0.1). Multipl...

  19. NOGAP B. 2; Zooplankton data from the Canadian Beaufort Sea shelf, 1986

    Energy Technology Data Exchange (ETDEWEB)

    Hopky, G.E.; Lawrence, M.J.; Chiperzak, D.B.

    1994-01-01

    To provide background data for assessing the implications of hydrocarbon development on the Canadian Arctic coastal shelf, zooplankton were collected from the Canadian Beaufort Sea shelf in May (ice on), and July to September (open water) of 1986 under the Northern Oil and Gas Program (NOGAP). In May, 4 Wisconsin net samples were collected from two stations. In July to September, 89, 88 and 181 net samples were collected with neuston, 85 [mu]m bongo and 500[mu]m bongo gear, respectively, from 49 stations. Neuston gear sampled at the water surface, while other gear sampled the water column. There were 247 taxonomic identifications, from 30 taxonomic groups. Copepods predominated a total catch of 33.66 million specimens. Wet and dry biomass data by taxonomic group are given for neuston and 500 [mu]m bongo net samples. Respective maximum wet and dry sample biomass for neuston samples was 44.15 and 5.52 g/100 m[sup 3] water filtered, and for bongo samples, 123.72 and 36.00 g/100 m[sup 3]. Length-frequency and sample caloric density data are given respectively, for copepod species captured in 23 samples, and 9 samples, from 500[mu]m bongo nets. 16 refs., 4 figs., 12 tabs.

  20. NOGAP B. 2; Zooplankton data from the Canadian Beaufort Sea shelf, 1984 and 1985

    Energy Technology Data Exchange (ETDEWEB)

    Hopky, G.E.; Lawrence, M.J.; Chiperzak, D.B.

    1994-01-01

    To provide background data for assessing the implications of hydrocarbon development on the Canadian Arctic coastal shelf, zooplankton were collected from the Canadian Beaufort Sea shelf in July and September, 1984 and in July and September, 1985 under the Northern Oil and Gas Program (NOGAP). In 1984, 18 and 16 net samples were collected with 763[mu]m Wisconsin and 500 [mu]m neuston gear, respectively, from 18 stations. In 1985, 123, 54 and 229 net samples were collected with 500 [mu]m neuston, 85 [mu]m bongo and 500[mu]m bongo gear, respectively, from 60 stations. Neuston gear sampled at the water surface, while other gear sampled the water column. In 1984, 309,068 specimens were caught, with 64 taxonomic identifications from 15 taxonomic groups. In 1985 there were 210 taxonomic identifications, representative of 32 taxonomic groups, and a total catch of 22.38 million specimens. Copepods predominated in all catches. Wet and dry biomass data of individual specimens for most taxonomic groups are given for the 1985 samples. The maximum sample dry biomass for 1985 neuston and 500 [mu]m bongo samples were 10.89 and 69.31 g/100 m[sup 3] of water filtered, respectively. Length-frequency data are given for 20 species, mostly copepods, captured in twenty-three 1985 500 [mu]m bongo net samples. 17 refs., 5 figs., 14 tabs.

  1. Aerial surveys of endangered whales in the Beaufort Sea, Fall 1989. Final report

    International Nuclear Information System (INIS)

    The OCSLA Amendments of 1978 (43 U.S.C. 1802) established a policy for the management of oil and natural gas in the OCS and for protection of the marine and coastal environments. The amended OCSLA authorizes the Secretary of the Interior to conduct studies in areas or regions of sales to ascertain the environmental impacts on the marine and coastal environments of the outer Continental Shelf and the coastal areas which may be affected by oil and gas development (43 U.S.C. 1346). The report describes field activities and data analyses for aerial surveys of bowhead whales conducted between 1 September 1989 and 20 October 1989 in the Beaufort Sea, primarily between 140 W. and 154 W. longitudes south of 72 N. latitude. Ice cover during September and October 1989 was exceptionally light. A total of 215 bowhead whales, 104 belukha whales, 9 bearded seals, 84 ringed seals, and 32 unidentified pinnipeds were observed in 1989 during 98.70 hours of survey effort that included 38.10 hours on randomized transects. The last sighting of a bowhead whale made during the survey occurred in open water on 19 October 1989. No whales were sighted during a subsequent flight on 20 October 1989. Estimated median and mean water depths were shallower than for previous surveys (1982-1989). This is consistent with a trend for whales to be located in shallower water during years of generally light ice cover

  2. Notice of availability, final environmental impact statement, Beaufort Sea oil and gas development/Northstar Project

    International Nuclear Information System (INIS)

    BP Exploration (Alaska) Inc. (BPXA) is proposing to develop the Northstar Unit, located approximately 6 miles offshore of Point Storkensen in the Alaskan Beaufort Sea. BPXA's proposed action is a self-contained development/production facility located on a reconstructed gravel island in 39 feet of water. Also proposed is construction of two buried subsea pipelines between the island and shoreline to transport oil and gas. The pipelines would connect with onshore facilities and the Trans Alaska Pipeline System (TAPS). In response to BPXA's submittal of a permit application under Section 10 of the Rivers and Harbors Act, Section 404 of the Clean Water Act, and Section 103 of the Marine Protection Research and Sanctuaries Act, the US Army Corps of engineers, Alaska District (Corps) determined that issuance of a permit for BPXA's proposed project constituted a major federal action that may significantly affect the quality of the human environment pursuant to the National Environmental Policy Act (NEPA). In addition, the US Environmental Protection Agency (EPA), determined under provisions of the Clean Water Act and 40 CFR Part 6 Subpart F that permitting by the EPA for BPXA's proposed project also constituted a major federal action that my significantly affect the quality of the human environment. As a result, preparation of an Environmental Impact Statement (EIS) under NEPA was undertaken to identify and evaluate a range of reasonable alternatives and evaluate the potential effects the alternates, including BPXA's proposed project, may have on the human environment

  3. Options for integrated resource management in the Mackenzie Delta-Beaufort Sea region

    International Nuclear Information System (INIS)

    Examples of consultative activities and environmental protection measures are reviewed which have been employed in the Mackenzie Delta/Beaufort Sea region by one or more petroleum operators to achieve successful integrated land use during the past 20 years. The review illustrates how petroleum operators, in cooperation with local residents and communities, have planned and adapted specific aspects of different projects to address and resolve environmental and community concerns, and provides an overview of the measures that can be employed to achieve integrated land use planning guidelines for future projects. The review focuses on specific groups of renewable resources and the applicable measures that have been used to reduce industrial impacts to these resources which are very important to local residents. Community consultation processes in the planning region have been successfully used by local residents, government, and industry to identify concerns associated with petroleum projects, and to develop appropriate measures to address these concerns. Environmental protection planning measures are described for cultural and historical resources, air quality, noise, freshwater quality, marine water quality, terrain and soils, fisheries, and terrestrial and marine wildlife. General measures as well as specific protection procedures such as the beluga whale protection plan and oil spill contingency plans are discussed. Although some environmental accidents have occurred during petroleum exploration and drilling activities, evidence suggests that petroleum activity has been able to proceed with no detectable long-term impacts to the environment. 30 refs., 1 fig

  4. Marine heat flow measurements across subsea permafrost limit in the eastern Mackenzie Trough, Canadian Beaufort Sea

    Science.gov (United States)

    Kim, Y. G.; Hong, J. K.; Jin, Y. K.; Riedel, M.; Melling, H.; Kang, S. G.; Dallimore, S.

    2015-12-01

    Marine heat flow measurements using a 5 m-long Ewing-type heat probe were made during Korean icebreaker R/V Araon's Arctic expeditions (ARA04C in 2013 and ARA05B in 2014) to better know the shallow subsurface thermal structure in the eastern slope of Mackenzie Trough, the Canadian Beaufort Sea, in which associative geological processes of permafrost degradation and gas hydrate dissociation occur because of long-term warming since the Last Glacial Maximum. Heat flow in the continental slope was collected for the first time and is rather higher than those from deep boreholes (up to a few km below the seafloor) in the continental shelf. However, the smaller geothermal gradient and thermal conductivity were observed from sites along a transect line across permafrost limit on the eastern slope of the trough. It is noted that geothermal gradients are relatively constant in the vicinity of permafrost limit but are much smaller (even minus) only at deeper depths with positive bottom water temperature. Reason for such distribution is unclear yet. Based on observed geothermal gradient and bottom water temperature, permafrost table shown in subbottom profile seems to be controlled not by temperature. On the other hand, our finding of permafrost evidence on the other subbottom profile located landward may support that permafrost limit in the trough is along with ~100 m isobath.

  5. Degradation state of organic matter in surface sediments from the Southern Beaufort Sea: a lipid approach

    Science.gov (United States)

    Rontani, J.-F.; Charriere, B.; Petit, M.; Vaultier, F.; Heipieper, H. J.; Link, H.; Chaillou, G.; Sempéré, R.

    2012-09-01

    For the next decades significant climatic changes should occur in the Arctic zone. The expected destabilisation of permafrost and its consequences for hydrology and plant cover should increase the input of terrigenous carbon to coastal seas. Consequently, the relative importance of the fluxes of terrestrial and marine organic carbon to the seafloor will likely change, strongly impacting the preservation of organic carbon in Arctic marine sediments. Here, we investigated the lipid content of surface sediments collected on the Mackenzie basin in the Beaufort Sea. Particular attention was given to biotic and abiotic degradation products of sterols and monounsaturated fatty acids. By using sitosterol and campesterol degradation products as tracers of the degradation of terrestrial higher plant inputs and brassicasterol degradation products as tracers of degradation of phytoplanktonic organisms, it could be observed that autoxidation, photooxidation and biodegradation processes act much more intensively on higher plant debris than on phytoplanktonic organisms. Examination of oxidation products of monounsaturated fatty acids showed that photo- and autoxidation processes act more intensively on bacteria than on phytodetritus. Enhanced damages induced by singlet oxygen (transferred from senescent phytoplanktonic cells) in bacteria were attributed to the lack of an adapted antioxidant system in these microorganisms. The strong oxidative stress observed in the sampled sediments resulted in the production of significant amounts of epoxy acids and unusually high proportions of monounsaturated fatty acids with a trans double bond. The formation of epoxy acids was attributed to peroxygenases (enzymes playing a protective role against the deleterious effects of fatty acid hydroperoxides in vivo), while cis/trans isomerisation was probably induced by thiyl radicals produced during the reaction of thiols with hydroperoxides. Our results confirm the important role played by abiotic

  6. Physical, profile and underway data collected aboard the Sikuliaq during cruise SKQ201511S in the Arctic Ocean, Beaufort Sea and Bering Sea from 2015-08-23 to 2015-09-26 (NCEI Accession 0145965)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0145965 includes physical, profile and underway data collected aboard the Sikuliaq during cruise SKQ201511S in the Arctic Ocean, Beaufort Sea and...

  7. Biological, chemical and other data collected aboard the HEALY during cruise HLY1201 in the Arctic Ocean, Beaufort Sea and Bering Sea from 2012-08-09 to 2012-08-25 (NODC Accession 0116859)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC accession 0116859 includes biological, chemical, optical and physical data collected aboard the HEALY during cruise HLY1201 in the Arctic Ocean, Beaufort Sea...

  8. Modeling seasonal variations of ocean and sea ice circulation in the Beaufort and Chukchi Seas: A model-data fusion study

    Institute of Scientific and Technical Information of China (English)

    WANG Jia; Kohei Mizobata; HU Haoguo; JIN Mei-bing; ZHANG Sheng; Walter Johnson; Koji Shimada; Moto Ikeda

    2008-01-01

    A 3.8-km Coupled Ice-Ocean Model (CIOM) was implemented to successfully reproduce many observed phenomena in the Beaufort and Chukchi seas, including the Bering-inflow-originated coastal current that splits into three branches:Alaska Coastal Water (ACW) , Central Channel, and Herald Valley branches. Other modeled phenomena include the Beaufort Slope Current (BSC) , the Beautort Gyre,the East Siberian Current (ESC), mesoscale eddies, seasonal landfast ice, sea ice ridging, shear, and deformation. Many of these downscaling processes can only be captured by using a high-resolution C1OM, nested in a global climate model. The seasonal cycles for sea ice concentration, thickness, velocity, and other variables are well reproduced with solid validation by satellite measurements. The seasonal cycles for upper ocean dynamics and thermodynamics are also well reproduced, which inelude the formation of the cold saline layer due to the injection of salt during sea ice formation, the BSC, and the subsurface upwelling in winter that brings up warm, even more saline Atlantic Water along the shelfbreak and shelf along the Beaufort coast.

  9. Stopover ecology of Semipalmated Sandpipers (Calidris pusilla) at coastal deltas of the Beaufort Sea, Alaska

    Science.gov (United States)

    Churchwell, Roy T.

    Avian migration is one of the wonders of the natural world. Stored fats are the main source of nutrients and fuel for avian migration and it is assumed the fat deposition at stopover sites is a critical component of a successful migration. Stopover sites are crucial in the successful migration of many birds, but particularly for arctic-breeding shorebirds that migrate long distances from breeding to wintering grounds. Despite the importance of stopover sites, it is often difficult to determine the importance of these sites to migrating shorebirds. I investigated three aspects of stopover ecology of Semipalmated Sandpipers (Calidris pusilla) foraging at coastal deltas on the Beaufort Sea coast, Alaska. First, I quantified the spatial and temporal distribution and abundance of the benthic macroinvertebrate community living within the mudflats. I found that there were two ecological groups of macroinvertebrates using river deltas, one originated in terrestrial freshwater habitats and most importantly could withstand freezing in delta sediments over the winter, and the other originated from the marine environment, could not withstand freezing and had to migrate to intertidal habitats each summer from deeper water areas that did not freeze over the winter. Stable isotope analysis allowed me to describe the origin of carbon consumed by invertebrates in intertidal habitats. I predicted freshwater invertebrates would consume terrestrial carbon, and marine invertebrates would consume marine carbon, but I found that both groups utilized the same carbon, which was a mixture of terrestrial and marine sources. My second research question determined the importance of delta foraging habitat for fall migrating Semipalmated Sandpipers. I mapped the temporal distribution and abundance of birds and quantified this relationship to invertebrate distribution and abundance. I researched fattening rates of shorebirds by measuring triglycerides in the blood of shorebirds I captured. I

  10. Photoproduction of ammonium in the southeastern Beaufort Sea and its biogeochemical implications

    Directory of Open Access Journals (Sweden)

    H. Xie

    2012-08-01

    Full Text Available Photochemistry of dissolved organic matter (DOM plays an important role in marine biogeochemical cycles, including the regeneration of inorganic nutrients. DOM photochemistry affects nitrogen cycling by converting bio-refractory dissolved organic nitrogen to labile inorganic nitrogen, mainly ammonium (NH4+. During the August 2009 Mackenzie Light and Carbon (MALINA Program, the absorbed photon-based efficiency spectra of NH4+ photoproduction (i.e. photoammonification were determined using water samples from the SE Beaufort Sea, including the Mackenzie River estuary, shelf, and Canada Basin. The photoammonification efficiency decreased with increasing wavelength across the ultraviolet and visible regimes and was higher in offshore waters than in shelf and estuarine waters. The efficiency was positively correlated with the molar nitrogen:carbon ratio of DOM and negatively correlated with the absorption coefficient of chromophoric DOM (CDOM. Combined with collateral measurements of CO2 and CO photoproduction, this study revealed a stoichiometry of DOM photochemistry with a CO2 : CO : NH4+ molar ratio of 165 : 11 : 1 in the estuary, 60 : 3 : 1 on the shelf, and 18 : 2 : 1 in the Canada Basin. The NH4+ efficiency spectra, along with solar photon fluxes, CDOM absorption coefficients and sea ice concentrations, were used to model the monthly surface and depth-integrated photoammonification rates in 2009. The summertime (June–August rates at the surface reached 6.6 nmol l−1 d−1 on the Mackenzie Shelf and 3.7 nmol l−1 d−1 further offshore; the depth-integrated rates were correspondingly 8.8 μmol m−2 d−1 and 11.3 μmol m−2 d−1. The offshore depth-integrated rate in August (8.0 μmol m−2 d−1 was comparable to the

  11. Apparent optical properties of the Canadian Beaufort Sea – Part 1: Observational overview and water column relationships

    Directory of Open Access Journals (Sweden)

    D. Antoine

    2013-07-01

    Full Text Available A data set of radiometric measurements collected in the Beaufort Sea (Canadian Arctic in August 2009 (Malina project is analyzed in order to describe apparent optical properties (AOPs in this sea, which has been subject to dramatic environmental changes for several decades. The two properties derived from the measurements are the spectral diffuse attenuation coefficient for downward irradiance, Kd, and the spectral remote sensing reflectance, Rrs. The former controls light propagation in the upper water column. The latter determines how light is backscattered out of the water and becomes eventually observable from a satellite ocean color sensor. The data set includes offshore clear waters of the Beaufort Basin as well as highly turbid waters of the Mackenzie River plumes. In the clear waters, we show Kd values that are much larger in the ultraviolet and blue parts of the spectrum than what could be anticipated considering the chlorophyll concentration. A larger contribution of absorption by colored dissolved organic matter (CDOM is responsible for these high Kd values, as compared to other oligotrophic areas. In turbid waters, attenuation reaches extremely high values, driven by high loads of particulate materials and also by a large CDOM content. In these two extreme types of waters, current satellite chlorophyll algorithms fail. This questions the role of ocean color remote sensing in the Arctic when Rrs from only the blue and green bands are used. Therefore, other parts of the spectrum (e.g., the red should be explored if one aims at quantifying interannual changes in chlorophyll in the Arctic from space. The very peculiar AOPs in the Beaufort Sea also advocate for developing specific light propagation models when attempting to predict light availability for photosynthesis at depth.

  12. NOGAP B. 2; Zooplankton data from the Canadian Beaufort Sea shelf, 1987 and 1988

    Energy Technology Data Exchange (ETDEWEB)

    Hopky, G.E.; Lawrence, M.J.; Chiperzak, D.B.

    1994-01-01

    To provide background data for assessing the implications of hydrocarbon development on the Canadian Arctic coastal shelf, zooplankton were collected from the Canadian Beaufort Sea shelf in May (ice on), and July and August (open water) of 1987, and March, 1988 under the Northern Oil and Gas Program (NOGAP). In May 1987, ten 63[mu]m Wisconsin net samples were collected from five stations. In July and August, 66, 61 and 138 net samples were collected with 500 [mu]m neuston, 85 [mu]m bongo and 500[mu]m bongo gear, respectively, from 35 stations. In March 1988, 10 Wisconsin net samples were collected from five stations. Neuston gear sampled at the water surface, while other gear sampled the water column. In 1987 there were 276 taxonomic identifications, from 29 taxonomic groups. Copepods predominated a total catch of 19.38 million specimens. Wet and dry biomass data by taxonomic group are given for neuston and 500 [mu]m bongo net samples. Respective maximum wet and dry sample biomass for neuston samples was 7.31 and 1.93 g/100 m[sup 3] water filtered, and for bongo samples, 44.0 and 12.5 g/100 m[sup 3]. Length-frequency and sample caloric density data are given respectively, for species captured in 17 samples, and 11 samples, from 500[mu]m bongo nets. In 1988, 18,278 specimens, mostly copepods were caught, with 30 taxonomic identifications from 10 taxonomic groups. 18 refs., 4 figs., 16 tabs.

  13. Modern erosion rates and loss of coastal features and sites, Beaufort Sea coastline, Alaska

    Science.gov (United States)

    Jones, Benjamin M.; Hinkel, Kenneth M.; Arp, C.D.; Eisner, Wendy R.

    2008-01-01

    This study presents modern erosion rate measurements based upon vertical aerial photography captured in 1955, 1979, and 2002 for a 100 km segment of the Beaufort Sea coastline. Annual erosion rates from 1955 to 2002 averaged 5.6 m a-1. However, mean erosion rates increased from 5.0 m a-1 in 1955-79 to 6.2 m a-1 in 1979-2002. Furthermore, from the first period to the second, erosion rates increased at 60% (598) of the 992 sites analyzed, decreased at 31% (307), and changed less than ?? 30 cm at 9% (87). Historical observations and quantitative studies over the past 175 years allowed us to place our erosion rate measurements into a longer-term context. Several of the coastal features along this stretch of coastline received Western place names during the Dease and Simpson expedition in 1837, and the majority of those features had been lost by the early 1900s as a result of coastline erosion, suggesting that erosion has been active over at least the historical record. Incorporation of historical and modern observations also allowed us to detect the loss of both cultural and historical sites and modern infrastructure. U.S. Geological Survey topographic maps reveal a number of known cultural and historical sites, as well as sites with modern infrastructure constructed as recently as the 1950s, that had disappeared by the early 2000s as a result of coastal erosion. We were also able to identify sites that are currently being threatened by an encroaching coastline. Our modern erosion rate measurements can potentially be used to predict when a historical site or modern infrastructure will be affected if such erosion rates persist. ?? The Arctic Institute of North America.

  14. Benthic Gouge Marks in the Canadian Beaufort Sea: Associations Between Whales and Methane Seeps?

    Science.gov (United States)

    Smalls, P. T.; Paull, C. K.; Dallimore, S.

    2015-12-01

    Numerous distinctive depressions were observed on the seafloor during twenty-eight remotely operated vehicle (ROV) dives conducted on the shelf edge and upper slope of the Canadian Beaufort Sea. Surface ship and autonomous underwater vehicle (AUV) multibeam bathymetric maps were used to identify potential methane seepage sites, such as areas with persistent water column acoustic anomalies and the tops of mud volcanoes. ROV dives were conducted at these sites and at background sites for stratigraphic sampling. The high abundance of these distinctive depressions stimulated an analysis of the video observations made on these ROV dives. Depressions were analyzed to document their characteristics, to help determine their origin, and to establish whether their frequency varies with bottom type. One hundred fifty-two of the depressions observed had shared characteristics consisting of an "oval-shaped" depression with raised ridged edges that extended laterally along the flanks, and traces of uplifted sediment either in or around the depression. Similar depressions have been called "gouge marks" and attributed to bottom feeding beaked whales in previous studies. The size and water depth of the measured depressions matched well with beak sizes and feeding depths of beaked whale species known to exist in this area. This supports the conclusion that beaked whales created the depressions. The occurrence of these gouge marks and the estimates of the total area observed on these ROV dives (~45,000 m2), suggests they are common (e.g., ~4,000 per km2) features on the seafloor in this area of the Arctic. Gouges were also found 2.25 times more often at suspected methane seep-sites when normalized for depth and area. This suggests that the whales are preferentially attracted to seepage sites. While the reason for this possible preferential feeding behavior is unknown, it provides an intriguing avenue for further research.

  15. A Summary Comparison of Active Acoustic Detections and Visual Observations of Marine Mammals in the Canadian Beaufort Sea.

    Science.gov (United States)

    Pyć, Cynthia D; Geoffroy, Maxime; Knudsen, Frank R

    2016-01-01

    Fisheries sonar was used to determine the applicability of active acoustic monitoring (AAM) for marine mammal detection in the Canadian Beaufort Sea. During 170 h of simultaneous observation by marine mammal observers and active acoustic observation, 119 Balaena mysticetus (bowheads) and 4 Delphinapterus leucas (belugas) were visually sighted, while 59 acoustic signals of bowheads were detected by AAM operators. Observations and detection of seals were also recorded. Comparative results indicate that commercially available active acoustic systems can detect seals at distances up to 500 m and large baleen whales at distances up to 2 km. PMID:26611045

  16. Catalogue of polar bear (Ursus maritimus) maternal den locations in the Beaufort Sea and neighboring regions, Alaska, 1910-2010

    Science.gov (United States)

    Durner, George M.; Fischbach, Anthony S.; Amstrup, Steven C.; Douglas, David C.

    2010-01-01

    This report presents data on the approximate locations and methods of discovery of 392 polar bear (Ursus maritimus) maternal dens found in the Beaufort Sea and neighboring regions between 1910 and 2010 that are archived by the U.S. Geological Survey, Alaska Science Center, Anchorage, Alaska. A description of data collection methods, biases associated with collection method, primary time periods, and spatial resolution are provided. Polar bears in the Beaufort Sea and nearby regions den on both the sea ice and on land. Standardized VHF surveys and satellite radio telemetry data provide a general understanding of where polar bears have denned in this region over the past 3 decades. Den observations made during other research activities and anecdotal reports from other government agencies, coastal residents, and industry personnel also are reported. Data on past polar bear maternal den locations are provided to inform the public and to provide information for natural resource agencies in planning activities to avoid or minimize interference with polar bear maternity dens.

  17. Beaufort Sea deep-water gas hydrate recovery from a seafloor mound in a region of widespread BSR occurrence

    Science.gov (United States)

    Hart, Patrick E.; Pohlman, John W.; Lorenson, T.D.; Edwards, Brian D.

    2011-01-01

    Gas hydrate was recovered from the Alaskan Beaufort Sea slope north of Camden Bay in August 2010 during a U.S. Coast Guard Cutter Healy expedition (USCG cruise ID HLY1002) under the direction of the U.S. Geological Survey (USGS). Interpretation of multichannel seismic (MCS) reflection data collected in 1977 by the USGS across the Beaufort Sea continental margin identified a regional bottom simulating reflection (BSR), indicating that a large segment of the Beaufort Sea slope is underlain by gas hydrate. During HLY1002, gas hydrate was sampled by serendipity with a piston core targeting a steep-sided bathymetric high originally thought to be an outcrop of older, exposed strata. The feature cored is an approximately 1100m diameter, 130 m high conical mound, referred to here as the Canning Seafloor Mound (CSM), which overlies the crest of a buried anticline in a region of sub-parallel compressional folds beneath the eastern Beaufort outer slope. An MCS profile shows a prominent BSR upslope and downslope from the mound. The absence of a BSR beneath the CSM and occurrence of gas hydrate near the summit indicates that free gas has migrated via deep-rooted thrust faults or by structural focusing up the flanks of the anticline to the seafloor. Gas hydrate recovered from near the CSM summit at a subbottom depth of about 5.7 meters in a water depth of 2538 m was of nodular and vein-filling morphology. Although the hydrate was not preserved, residual gas from the core liner contained >95% methane by volume when corrected for atmospheric contamination. The presence of trace C4+hydrocarbons (hydrate lenses is also a likely factor in CSM growth. Pore water analysis shows the sulfate-methane transition to be very shallow (0-1 mbsf), also supporting an active high-flux interpretation. Pore water with chloride concentrations as low as 160 mM suggest fluid migration pathways may extend to the mound from buried non-marine sediments containing low-salinity fluids.

  18. Hematology of southern Beaufort Sea polar bears (2005-2007): Biomarker for an arctic ecosystem health sentinel

    Science.gov (United States)

    Kirk, Cassandra M.; Amstrup, S.; Swor, Rhonda; Holcomb, Darce; O'Hara, T. M.

    2010-01-01

    Declines in sea-ice habitats have resulted in declining stature, productivity, and survival of polar bears in some regions. With continuing sea-ice declines, negative population effects are projected to expand throughout the polar bear's range. Precise causes of diminished polar bear life history performance are unknown, however, climate and sea-ice condition change are expected to adversely impact polar bear (Ursus maritimus) health and population dynamics. As apex predators in the Arctic, polar bears integrate the status of lower trophic levels and are therefore sentinels of ecosystem health. Arctic residents feed at the apex of the ecosystem, thus polar bears can serve as indicators of human health in the Arctic. Despite their value as indicators of ecosystem welfare, population-level health data for U.S. polar bears are lacking. We present hematological reference ranges for southern Beaufort Sea polar bears. Hematological parameters in southern Beaufort Sea polar bears varied by age, geographic location, and reproductive status. Total leukocytes, lymphocytes, monocytes, eosinophils, and serum immunoglobulin G were significantly greater in males than females. These measures were greater in nonlactating females ages ???5, than lactating adult females ages ???5, suggesting that females encumbered by young may be less resilient to new immune system challenges that may accompany ongoing climate change. Hematological values established here provide a necessary baseline for anticipated changes in health as arctic temperatures warm and sea-ice declines accelerate. Data suggest that females with dependent young may be most vulnerable to these changes and should therefore be a targeted cohort for monitoring in this sentinel. ?? 2010 International Association for Ecology and Health.

  19. Sea-ice algae: Major contributors to primary production and algal biomass in the Chukchi and Beaufort Seas during May/June 2002

    Science.gov (United States)

    Gradinger, Rolf

    2009-08-01

    Sea-ice and water samples were collected at 14 stations on the shelves and slope regions of the Chukchi and Beaufort Seas during the spring 2002 expedition as part of the Shelf-Basin Interaction Studies. Algal pigment content, particulate organic carbon and nitrogen, and primary productivity were estimated for both habitats based on ice cores, brine collection and water samples from 5-m depth. The pigment content (0.2-304.3 mg pigments m -2) and primary productivity (0.1-23.0 mg C m -3 h -1) of the sea-ice algae significantly exceeded water-column parameters (0.2 and 1.0 mg pigments m -3; herbivores in early spring in the Chukchi and Beaufort Seas. Stable isotope signatures for ice and water samples did not differ significantly for δ 15N, but for δ 13C (ice: -25.1‰ to -14.2‰; water: -26.1‰ to -22.4‰). The analysis of nutrient concentrations and the pulse-amplitude-modulated fluorescence signal of ice algae and phytoplankton indicate that nutrients were the prime limiting factor for sea-ice algal productivity. The estimated spring primary production of about 1-2 g C m -2 of sea-ice algae on the shelves requires the use of substantial nutrient reservoirs from the water column.

  20. Seawater methane flux, methane oxidation rates, and methane sources on the Central US Beaufort Sea Continental Shelf

    Science.gov (United States)

    Pohlman, J.; Pack-Woo, M.; Xu, X.; Ruppel, C. D.; Casso, M.; Worley, C.

    2012-12-01

    Previous studies have shown that some shallow-water circum-Arctic Ocean continental shelves (e.g., the Laptev Sea) are releasing substantial methane to the atmosphere. A number of processes -- including microbial degradation of organic matter in shallow sediments or in deeper sediments that were only recently thawed from permafrost, the dissociation of gas hydrates that formed in association with permafrost, and leakage from deeper thermogenic reservoirs -- may contribute to these methane fluxes. In August 2012, the USGS Gas Hydrates Project, with sponsorship from the DOE Methane Hydrates R&D Program, conducted a cross-shelf survey of greenhouse gas fluxes, carbon isotopic signatures of methane and CO2, and methane oxidation rates on the Central US Beaufort Sea continental shelf. IODP drilling has been proposed for a shelf-to-upper continental slope transect on this part of the Alaskan Beaufort passive margin to unravel the history of late Pleistocene to contemporary climate warming and sea level rise. The work presented here complements a 2012 USGS multichannel seismic program intended as IODP site survey. The flux, isotopic, and oxidation rate surveys sampled nearshore areas still underlain by subsea permafrost, a location where relict gas hydrate previously associated with permafrost may still exist and extend across the shelf to where present-day methane release is likely dominated by microbial methane generated in situ. The new geochemical data were acquired using dedicated cavity ringdown spectrometers (CRDS) for the atmospheric and sea surface measurements. The seawater CRDS also characterized the carbon isotopic signature of the CO2 and CH4 in real-time. Oxidation rate measurements were carried out using the low level 14C-CH4 (LL 14C) tracer method. Continuous measurements of surface air and surface seawater methane and carbon dioxide concentration, in conjunction with relevant meteorological and water chemistry data, permit us to calculate sea

  1. Long-distance swimming by polar bears (Ursus maritimus) of the southern Beaufort Sea during years of extensive open water

    Science.gov (United States)

    2014-01-01

    Polar bears (Ursus maritimus Phipps, 1774) depend on sea ice for catching marine mammal prey. Recent sea-ice declines have been linked to reductions in body condition, survival, and population size. Reduced foraging opportunity is hypothesized to be the primary cause of sea-ice-linked declines, but the costs of travel through a deteriorated sea-ice environment also may be a factor. We used movement data from 52 adult female polar bears wearing Global Positioning System (GPS) collars, including some with dependent young, to document long-distance swimming (>50 km) by polar bears in the southern Beaufort and Chukchi seas. During 6 years (2004-2009), we identified 50 long-distance swims by 20 bears. Swim duration and distance ranged from 0.7 to 9.7 days (mean = 3.4 days) and 53.7 to 687.1 km (mean = 154.2 km), respectively. Frequency of swimming appeared to increase over the course of the study. We show that adult female polar bears and their cubs are capable of swimming long distances during periods when extensive areas of open water are present. However, long-distance swimming appears to have higher energetic demands than moving over sea ice. Our observations suggest long-distance swimming is a behavioral response to declining summer sea-ice conditions.

  2. Sharing Remote and Local Information for Tracking Spring Breakup in the Mackenzie Delta and Beaufort Sea

    Science.gov (United States)

    Forbes, D. L.; Whalen, D.; Fraser, P.

    2015-12-01

    The Mackenzie Delta is the second largest on the Arctic Ocean, covering 13 000 km2. The annual flood regime in the delta is dominated by the spring snowmelt freshet and associated ice breakup, as water from the south arrives in the ice-covered delta and spreads over bottomfast and adjacent floating sea ice at the delta front. The complex processes of water-ice interaction, flow partitioning, and overbank flooding to replenish waters in 43 000 delta lakes threaten community, transportation, subsistence, and energy infrastructure in the delta. The annual breakup season is a time of rejuvenation, excitement, and anxiety for delta residents and stakeholders. To track the progress of breakup and meet the need for knowledge dissemination to the local communities, a Mackenzie-Beaufort breakup newsletter has been produced by Natural Resources Canada on a quasi-daily basis during the May-June spring flood season for 10 years, and distributed to an e-mail list that grew to over 300 subscribers. This provides near real-time tracking of water levels and breakup using on-line gauges (Environment Canada), daily MODIS satellite imagery (NASA), Landsat imagery (USGS) and intermittent radar imagery (various sources). In earlier years, information was also supplied from field programs operating in the delta during breakup, but changing priorities and funding have reduced the number of outside researchers present during these critical weeks. Meanwhile the number of local contributors has grown, providing observations and photographs to share with the local, regional and global readership. In this way the newsletter evolved into a two-way communication tool and community portal. The newsletter is a chronicle of each breakup season and a key resource for territorial and municipal managers, subsistence organizations, and emergency response agencies, with routine requests for specific imagery in areas of concern. With the completion of 10 years under the present model, we are exploring

  3. Slope Edge Deformation and Permafrost Dynamics Along the Arctic Shelf Edge, Beaufort Sea, Canada

    Science.gov (United States)

    Paull, C. K.; Dallimore, S.; Caress, D. W.; Gwiazda, R.; Lundsten, E. M.; Anderson, K.; Riedel, M.; Melling, H.

    2015-12-01

    The shelf of the Canadian Beaufort Sea is underlain by relict offshore permafrost that formed in the long intervals of terrestrial exposure during glacial periods. At the shelf edge the permafrost thins rapidly and also warms. This area has a very distinct morphology that we attribute to both the formation and degradation of ice bearing permafrost. Positive relief features include circular to oval shaped topographic mounds, up to 10 m high and ~50 m in diameter which occur at a density of ~6 per km2. Intermixed are circular topographic depressions up to 20 m deep. This topography was investigated using an autonomous underwater vehicle that provides 1 m horizontal resolution bathymetry and chirp profiles, a remotely operated vehicle to document seafloor textures, and sediment cores to sample pore waters. A consistent down-core freshening at rates of 14 to 96 mM Cl- per meter was found in these pore waters near the shelf edge. Downward extrapolation of these trends indicates water with ≤335 mM Cl- should occur at 2.3 to 22.4 m sub-seafloor depths within this shelf edge deformation band. Pore water with 335 mM Cl- or less freezes at -1.4°C. As bottom water temperatures in this area are persistently (<-1.4°C) cold and ground ice was observed in some core samples, we interpret the volume changes associated with mound formation are in part due to pore water freezing. Thermal models (Taylor et al., 2014) predict brackish water along the shelf edge may be sourced in relict permafrost melting under the adjacent continental shelf. Buoyant brackish water is hypothesized to migrate along the base of the relict permafrost, to emerge at the shelf edge and then refreeze when it encounters the colder seafloor. Expansion generated by the formation of ice-bearing permafrost generates the positive relief mounds and ridges. The associated negative relief features may be related to permafrost dynamics also. Permafrost dynamics may have geohazard implications that are unique to the

  4. Carbon sources in the Beaufort Sea revealed by molecular lipid biomarkers and compound specific isotope analysis

    Directory of Open Access Journals (Sweden)

    I. Tolosa

    2012-10-01

    Full Text Available Molecular lipid biomarkers (hydrocarbons, alcohols, sterols and fatty acids and compound specific isotope analysis of suspended particulate organic matter (SPM and surface sediments of the Mackenzie Shelf and slope (Southeast Beaufort Sea, Arctic Ocean, were studied in summer 2009. The concentrations of the molecular lipid markers, characteristic of known organic matter sources, were grouped and used as proxies to evaluate the relative importance of fresh algal, detrital algal, fossil, C3 terrestrial plants, bacterial and zooplankton material in the sedimentary organic matter (OM.

    Fossil and detrital algal contributions were the major fractions of the freshwater SPM from the Mackenzie River with ~34% each of the total molecular biomarkers. Fresh algal, C3 terrestrial, bacterial and zooplanktonic components represented much lower percentages, 17, 10, 4 and < 1%, respectively. In marine SPM from the Mackenzie slope, the major contributions were fresh and detrital algal components (> 80% with a minor contribution of fossil and C3 terrestrial biomarkers. Characterization of the sediments revealed a major sink of refractory algal material mixed with some fresh algal material, fossil hydrocarbons and a small input of C3 terrestrial sources. In particular, the sediments from the shelf and at the mouth of the Amundsen Gulf presented the highest contribution of detrital algal material (60–75% whereas those from the slope contained the highest proportion of fossil (40% and C3 terrestrial plant material (10%. Overall, considering that the detrital algal material is marine derived, autochthonous sources contributed more than allochthonous sources to the OM lipid pool. Using the ratio of an allochthonous biomarker (normalized to total organic carbon, TOC found in the sediments to those measured at the river mouth water, we estimated that the fraction of terrestrial material preserved in the

  5. Partial pressure (or fugacity) of carbon dioxide, salinity and SEA SURFACE TEMPERATURE collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from Marcus G. Langseth in the Arctic Ocean, Beaufort Sea and others from 2010-05-07 to 2013-06-25 (NODC Accession 0109901)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0109901 includes Surface underway data collected from Marcus G. Langseth in the Arctic Ocean, Beaufort Sea, Bering Sea, Caribbean Sea, Cordell Bank...

  6. Surface and basal sea ice melt from autonomous buoy arrays during the 2014 sea ice retreat in the Beaufort/Chukchi Seas

    Science.gov (United States)

    Maksym, T. L.; Wilkinson, J.; Hwang, P. B.

    2014-12-01

    As the Arctic continues its transition to a seasonal ice cover, the nature and role of the processes driving sea ice retreat are expected to change. Key questions revolve around how the coupling between dynamics and thermodynamic processes and potential changes in the role of melt ponds contribute to an accelerated seasonal ice retreat. To address these issues, 44 autonomous platforms were deployed in four arrays in the Beaufort Sea in March, 2014, with an additional array deployed in August in the Chukchi Sea to monitor the evolution of ice conditions during the seasonal sea ice retreat. Each "5-dice" array included four or five co-sited ice mass balance buoys (IMB) and wave buoys with digital cameras, and one automatic weather station (AWS) at the array center. The sensors on these buoys, combined with satellite imagery monitoring the large-scale evolution of the ice cover, provide a near-complete history of the processes involved in the seasonal melt of sea ice. We present a preliminary analysis of the contributions of several key processes to the seasonal ice decay. The evolution of surface ponding was observed at several sites with differing ice types and surface morphologies. The records of surface melt and ice thickness demonstrate a key role of ice type in driving the evolution of the ice cover. Analysis of the surface forcing and estimates of solar energy partitioning between the surface and upper ocean is compared to the surface and basal mass balance from the IMBs. The role of ice divergence and deformation in driving sea ice decay - in particular its role in accelerating thermodynamic melt processes - is discussed.

  7. Dose Estimates from Ingestion of Marine and Terrestrial Animals Harvested in the Beaufort Sea and Northwestern Alaska

    Energy Technology Data Exchange (ETDEWEB)

    W. C. T. Inkret; M. E. Schillaci; D. W. Efurd; M. E. Ennis; M. J. Hameedi; J. M. Inkret; T. H. T. Little; G. Miller

    2000-11-01

    Between 1993 and 1995, marine and terrestrial animal samples were collected from the Beaufort Sea and northwest Alaska. These samples were analyzed at Los Alamos National Laboratory for the presence of the anthropogenic radionuclides, {sup 90}Sr, {sup 137}Cs, {sup 238}Pu, {sup 239+240}Pu, and {sup 241}Am. The measurement data were combined with food consumption rates based on survey results for populations residing in three northwest Alaskan communities and published age-dependent ingestion dose coefficients to estimate potential radiological impacts from the consumption of traditional animal foods harvested in this region. The results of this study indicate that committed equivalent doses to adults from {sup 90}Sr and {sup 137}Cs, due to consumption of traditional food sources are consistent with currently accepted estimates of average doses to adults in North America due to atmospheric nuclear weapons testing fallout.

  8. Marine animal sighting and census data from aircraft from the Beaufort Sea as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 25 May 1982 to 21 September 1982 (NODC Accession 8300121)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine animal sighting and census data were collected from aircraft from the Beaufort Sea from 25 May 1982 to 21 September 1982. Data were collected by the Alaska...

  9. Wind direction and other data from the Beaufort Sea as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 18 July 1978 to 01 September 1978 (NODC Accession 8300057)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Wind direction and other data were collected from the Beaufort Sea from 18 July 1978 to 01 September 1978. Data were collected by University of Washington (UW) as...

  10. Chemical, optical and other data collected aboard the HEALY during cruise HLY1101 in the Arctic Ocean, Beaufort Sea and others from 2011-06-25 to 2011-07-29 (NODC Accession 0104296)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC accession 0104296 includes chemical, optical, physical and underway data collected aboard the HEALY during cruise HLY1101 in the Arctic Ocean, Beaufort Sea and...

  11. Profile data from CTD casts aboard the F/V Ocean Explorer in the Arctic Ocean and Beaufort Sea from 2008-08-06 to 2008-08-22 (NODC Accession 0001920)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This profile data aboard the F/V Ocean Explorer in the Arctic Ocean and Beaufort Sea from August 6, 2008 to August 22, 2008 was supported by the Minerals Management...

  12. Pressure gauge and CTD data from ICE ISLANDS and other platforms from the Beaufort and Chukchi Seas in support of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 25 July 1982 to 08 March 1984 (NODC Accession 8500129)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Pressure gauge and CTD data were collected from the ICE ISLANDS and other platforms in the Beaufort and Chukchi Seas from 25 July 1982 to 08 March 1984. Data were...

  13. Physical, meteorological, and other data from surface sensors and CTD casts in the Beaufort Sea from helicopters as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 04 March 1977 to 11 March 1977 (NODC Accession 7700757)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical, meteorological, and other data were collected from surface sensors and CTD casts in the Beaufort Sea from helicopters. Data were collected by the...

  14. Physical, meteorological, and other data from surface sensors and CTD casts in the Beaufort Sea from helicopters as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 31 October 1976 to 04 November 1976 (NODC Accession 7700163)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical, meteorological, and other data were collected from surface sensors and CTD casts in the Beaufort Sea from helicopters. Data were collected by the...

  15. Physical, meteorological, and other data from surface sensors and CTD casts in the Beaufort Sea from helicopters as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 20 February 1976 to 29 February 1976 (NODC Accession 7601640)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical, meteorological, and other data were collected from surface sensors and CTD casts in the Beaufort Sea from helicopters. Data were collected by the...

  16. Physical, meteorological, and other data from surface sensors and CTD casts in the Beaufort Sea from helicopter as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 26 October 1975 to 10 November 1975 (NODC Accession 7601680)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical, meteorological, and other data were collected from surface sensors and CTD casts in the Beaufort Sea from helicopter. Data were collected by the...

  17. Acoustics short-term passive monitoring using sonobuoys in the Bering, Chukchi, and Western Beaufort Seas conducted by Alaska Fisheries Scientific Center, National Marine Mammal Laboratory from 2007-08-01 to 2015-09-28 (NCEI Accession 0138863)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Marine Mammal Laboratory (NMML) has conducted passive acoustic monitoring in the Bering, Chukchi, and Western Beaufort Seas to determine...

  18. Drifting buoy and other data from the Beaufort Sea as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 05 November 1975 to 01 October 1976 (NODC Accession 7700019)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Drifting buoy and other data was collected from the Beaufort Sea by the University of Washington (UW) as part of the Outer Continental Shelf Environmental...

  19. Drifting buoy and other data from the Beaufort Sea and other locations as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 03 March 1977 to 05 April 1977 (NODC Accession 7700543)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Drifting buoy data was collected from the Beaufort Sea and other locations by the University of Washington (UW) as part of the Outer Continental Shelf Environmental...

  20. Drifting buoy and other data from the Beaufort Sea and other locations as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 04 April 1977 to 03 July 1977 (NODC Accession 7700780)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Drifting buoy data was collected from the Beaufort Sea by the University of Washington (UW) as part of the Outer Continental Shelf Environmental Assessment Program...

  1. Drifting buoy and other data from the Arctic Ocean and Beaufort Sea as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 04 November 1975 to 01 October 1976 (NODC Accession 7700114)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Drifting buoy data was collected from the Arctic Ocean and Beaufort Sea by the University of Washington (UW) as part of the Outer Continental Shelf Environmental...

  2. Effluent - discharge descriptions and other data collected from several platforms using salinometer and other instruments in the Beaufort Sea from 07 August 1985 to 01 September 1985 (NODC Accession 8600317)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — F144 data were collected using salinometer and other instruments in the Beaufort Sea from several platforms. Data were collected from 07 August 1985 to 01 September...

  3. Physical, profile and underway data collected aboard the Sikuliaq during cruise SKQ201510S in the Arctic Ocean and Beaufort Sea from 2015-07-20 to 2015-08-22 (NCEI Accession 0145950)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0145950 includes physical, profile and underway data collected aboard the Sikuliaq during cruise SKQ201510S in the Arctic Ocean and Beaufort Sea from...

  4. Benthic organism and other data from bottom grabs from Helicopters in the Beaufort Sea as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 26 October 1975 to 19 March 1976 (NODC Accession 7601417)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Benthic organism and other data were collected in the Beaufort Sea from helicopters by the Oregon Stare University (OSU). Data were collected as part of the Outer...

  5. Environmental impact of the proposed Trans-Alaska pipeline on marine mammals in the Beaufort sea: Proposed Trans-Alaska Pipeline System potential environmental impact, possible loss of oil

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This paper describes the Beaufort Sea and how its characteristics would influence the course of fate of oil spills in generally predictable ways: currents would...

  6. Chemical, optical and physical data collected aboard the HEALY during cruise HLY1001 in the Arctic Ocean, Beaufort Sea and others from 2010-06-15 to 2010-07-22 (NODC Accession 0116856)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC accession 0116856 includes chemical, optical and physical data collected aboard the HEALY during cruise HLY1001 in the Arctic Ocean, Beaufort Sea and others...

  7. Chemical, optical and physical data collected aboard the HEALY during cruise HLY09TD in the Beaufort Sea from 2009-07-06 to 2009-07-25 (NODC Accession 0116855)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC accession 0116855 includes chemical, optical and physical data collected aboard the HEALY during cruise HLY09TD in the Beaufort Sea from 2009-07-06 to...

  8. Marine Toxic Substance and other data from core casts from the ALUMINIAK in the Beaufort Sea as part of Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 14 August 1977 to 25 August 1977 (NODC Accession 7900067)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine Toxic Substance and other data were collected from core casts in the Beaufort Sea from the ALUMINIAK. Data were collected by the University of Alaska -...

  9. Phytoplankton and other data from net and bottle casts in the Beaufort Sea from GLACIER as part of Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 07 August 1976 to 04 September 1976 (NODC Accession 7700337)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Phytoplankton and other data were collected from net and bottle casts in the Beaufort Sea from the GLACIER from 07 August 1976 to 04 September 1976. Data were...

  10. Benthic organism and other data from the Beaufort Sea from the GLACIER as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 19 August 1971 to 22 August 1972 (NODC Accession 7700213)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Benthic organism and other data were collected in the Beaufort Sea from the GLACIER by Oregon State University (OSU). Data were collected as part of the Outer...

  11. Fish survey - fishing duration, shellfish resource assessment, and other data from the Beaufort Sea as part of Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 22 June 1976 to 21 September 1976 (NODC Accession 7800003)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Fish survey, fishing duration, shellfish resource assessment, and other data were collected from the Beaufort Sea from 22 June 1976 to 21 September 1976. Data were...

  12. Fish survey, fishing duration and other data from beach seines and other gear in Beaufort Sea as part of Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 16 June 1977 to 24 September 1978 (NODC Accession 8200124)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Fish survey, fishing duration, and other data were collected from beach seines and other gear in the Beaufort Sea from 16 June 1977 to 24 September 1978. Data were...

  13. Fish survey, fishing duration, and other data from helicopter in the Beaufort Sea as part of Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 31 July 1975 to 22 September 1975 (NODC Accession 7601929)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Fish survey, fishing duration, and other data were collected from helicopter in the Beaufort Sea from 31 July 1975 to 22 September 1975. Data were submitted by the...

  14. Marine bird sighting and other data from platforms in the Beaufort Sea as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 11 June 1975 to 05 September 1975 (NODC Accession 7601518)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine bird sighting and other data were collected from platforms in the Beaufort Sea from 11 June 1975 to 05 September 1975. Data were collected by the University...

  15. Marine bird sighting and other data from platforms in the Beaufort Sea as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 08 June 1976 to 17 September 1976 (NODC Accession 7700308)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine bird sighting and other data were collected from platforms in the Beaufort Sea from 08 June 1976 to 17 September 1976. Data were collected by the University...

  16. Marine bird sighting and other data from the BARGE and other platforms from Beaufort Sea and other locations as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 07 May 1976 to 15 October 1976 (NODC Accession 7800031)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine bird sighting and other data were collected from the BARGE and other platforms from the Beaufort Sea and other locations from 07 May 1976 to 15 October 1976....

  17. Marine bird sighting and other data from the Beaufort Sea as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 27 July 1980 to 26 August 1980 (NODC Accession 8100692)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine bird sighting and other data were collected in the Beaufort Sea from 27 July 1980 to 26 August 1980. Data were collected by the University of California (UC)...

  18. Plankton and other data from net casts in the Beaufort Sea from the USCGC GLACIER and other platforms from 04 August 1972 to 17 May 1979 (NODC Accession 8000587)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Plankton and other data were collected using net casts in the Beaufort Sea from the USCGC GLACIER and other platforms from 04 August 1972 to 17 May 1979. Data were...

  19. Marine mammal observations collected by aircraft and ship and submitted as part of the ConocoPhillips and Shell Joint Monitoring Program in the Chukchi and Beaufort Seas, 2006-2010 (NODC Accession 0120532)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains vessel- and aircraft-based mammal sightings data and associated environmental data collected in the Chukchi and Beaufort seas during the open...

  20. Marine mammal specimen and other data from the Beaufort Sea and other locations as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 06 May 1979 to 12 October 1981 (NODC Accession 8200202)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine mammal specimen and other data were collected in the Beaufort Sea and other locations from 06 May 1979 to 12 October 1981. Data were collected by the...

  1. Benthic organism and other data from net casts in the Beaufort Sea as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 08 July 1978 to 23 September 1978 (NODC Accession 8000425)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Benthic organism and other data were collected from net casts in the Beaufort Sea by the Alaska Research Associates and LGL LTD. Data were collected as part of the...

  2. Evaluation of the anthropogenic radionuclide concentrations in sediments and fauna collected in the Beaufort Sea and northern Alaska

    International Nuclear Information System (INIS)

    This study was performed to establish a quality controlled data set about the levels of radio nuclide activity in the environment and in selected biota in the U.S. Arctic. Sediment and biota samples were collected by the National Oceanic and Atmospheric Administration (NOAA), the National Biological Service, and the North Slope Borough's Department of Wildlife Management to determine the impact of anthropogenic radionuclides in the Arctic. The results summarized in this report are derived from samples collected in northwest Alaska with emphasis on species harvested for subsistence in Barrow, Alaska. Samples were analyzed for the anthropogenic radionuclides 90Sr, 137Cs, 238Pu, 239Pu, 240Pu and 241Am. The naturally occurring radionuclides 40K, 212Pb and 214Pb were also measured. One goal of this study was to determine the amounts of anthropogenic radionuclides present in the Beaufort Sea. Sediment samples were isotopically fingerprinted to determine the sources of radio nuclide activities. Biota samples of subsistence and ecological value were analyzed to search for evidence of bio-accumulation of radionuclides and to determine the radiation exposures associated with subsistence living in northern Alaska. The anthropogenic radio nuclide content of sediments collected in the Beaufort Sea was predominantly the result of the deposition of global fallout. No other sources of anthropogenic radionuclides could be conclusively identified in the sediments. The anthropogenic radio nuclide concentrations in fish, birds and mammals were very low. Assuming that ingestion of food is an important pathway leading to human contact with radioactive contaminants and given the dietary patterns in coastal Arctic communities, it can be surmised that marine food chains are presently not significantly affected

  3. Estimating Arctic sea-ice freeze-up and break-up from the satellite record: A comparison of different approaches in the Chukchi and Beaufort Seas

    Directory of Open Access Journals (Sweden)

    Mark Johnson

    2016-09-01

    Full Text Available 1. Abstract The recognized importance of the annual cycle of sea ice in the Arctic to heat budgets, human behavior, and ecosystem functions, requires consistent definitions of such key events in the ice cycle as break-up and freeze-up. An internally consistent and reproducible approach to characterize the timing of these events in the annual sea-ice cycle is described. An algorithm was developed to calculate the start and end dates of freeze-up and break-up and applied to time series of satellite-derived sea-ice concentration from 1979 to 2013. Our approach builds from discussions with sea-ice experts having experience observing and working on the sea ice in the Bering, Chukchi and Beaufort Seas. Applying the algorithm to the 1979–2013 satellite data reveals that freeze-up is delayed by two weeks per decade for the Chukchi coast and one week per decade for the Beaufort coast. For both regions, break-up start is arriving earlier by 5–7 days per decade and break-up end is arriving earlier by 10–12 days per decade. In the Chukchi Sea, “early” break-up is arriving earlier by one month over the 34-year period and alternates with a “late” break-up. The calculated freeze-up and break-up dates provide information helpful to understanding the dynamics of the annual sea-ice cycle and identifying the drivers that modify this cycle. The algorithm presented here, and potential refinements, can help guide future work on changes in the seasonal cycle of sea ice. The sea-ice phenology of freeze-up and break-up that results from our approach is consistent with observations of sea-ice use. It may be applied to advancing our understanding and prediction of the timing of seasonal navigation, availability of ice as a biological habitat, and assessment of numerical models.

  4. Dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using Alkalinity titrator, CTD and other instruments from the JAKOV SMIRNITSKIY in the Beaufort Sea, East Siberia Sea and others from 2008-08-15 to 2008-09-16 (NODC Accession 0108368)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0108368 includes chemical, discrete sample, physical and profile data collected from JAKOV SMIRNITSKIY in the Beaufort Sea, East Siberia Sea, Kara...

  5. Partial pressure (or fugacity) of carbon dioxide, salinity and SEA SURFACE TEMPERATURE collected from underway - surface observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from the NATHANIEL B. PALMER in the Arctic Ocean, Beaufort Sea and others from 1994-11-04 to 2012-08-31 (NODC Accession 0083189)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0083189 includes chemical, physical and underway - surface data collected from NATHANIEL B. PALMER in the Arctic Ocean, Beaufort Sea, Bering Sea,...

  6. Dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, Coulometer for DIC measurement and other instruments from the MIRAI in the Beaufort Sea and Bering Sea from 2006-08-21 to 2006-09-29 (NODC Accession 0112268)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0112268 includes biological, chemical, discrete sample, physical and profile data collected from MIRAI in the Beaufort Sea and Bering Sea from...

  7. Synoptic evaluation of carbon cycling in Beaufort Sea during summer: contrasting river inputs, ecosystem metabolism and air-sea CO2 fluxes

    Science.gov (United States)

    Forest, A.; Coupel, P.; Else, B.; Nahavandian, S.; Lansard, B.; Raimbault, P.; Papakyriakou, T.; Gratton, Y.; Fortier, L.; Tremblay, J.-É.; Babin, M.

    2013-10-01

    The accelerated decline in Arctic sea ice combined with an ongoing trend toward a more dynamic atmosphere is modifying carbon cycling in the Arctic Ocean. A critical issue is to understand how net community production (NCP; the balance between gross primary production and community respiration) responds to changes and modulates air-sea CO2 fluxes. Using data collected as part of the ArcticNet-Malina 2009 expedition in southeastern Beaufort Sea (Arctic Ocean), we synthesize information on sea ice, wind, river, water column properties, metabolism of the planktonic food web, organic carbon fluxes and pools, as well as air-sea CO2 exchange, with the aim of identifying indices of ecosystem response to environmental changes. Data were analyzed to develop a non-steady-state carbon budget and an assessment of NCP against air-sea CO2 fluxes. The mean atmospheric forcing was a mild upwelling-favorable wind (~5 km h-1) blowing from the N-E and a decaying ice cover (600 mg C m-2d-1) over the shelf prior to our survey, (2) freshwater dilution by river runoff and ice melt, and (3) the presence of cold surface waters offshore. Only the Mackenzie River delta and localized shelf areas directly affected by upwelling were identified as substantial sources of CO2 to the atmosphere (>10mmol C m-2d-1). Although generally state.

  8. Synoptic evaluation of carbon cycling in the Beaufort Sea during summer: contrasting river inputs, ecosystem metabolism and air-sea CO2 fluxes

    Science.gov (United States)

    Forest, A.; Coupel, P.; Else, B.; Nahavandian, S.; Lansard, B.; Raimbault, P.; Papakyriakou, T.; Gratton, Y.; Fortier, L.; Tremblay, J.-É.; Babin, M.

    2014-05-01

    The accelerated decline in Arctic sea ice and an ongoing trend toward more energetic atmospheric and oceanic forcings are modifying carbon cycling in the Arctic Ocean. A critical issue is to understand how net community production (NCP; the balance between gross primary production and community respiration) responds to changes and modulates air-sea CO2 fluxes. Using data collected as part of the ArcticNet-Malina 2009 expedition in the southeastern Beaufort Sea (Arctic Ocean), we synthesize information on sea ice, wind, river, water column properties, metabolism of the planktonic food web, organic carbon fluxes and pools, as well as air-sea CO2 exchange, with the aim of documenting the ecosystem response to environmental changes. Data were analyzed to develop a non-steady-state carbon budget and an assessment of NCP against air-sea CO2 fluxes. During the field campaign, the mean wind field was a mild upwelling-favorable wind (~ 5 km h-1) from the NE. A decaying ice cover ( 600 mg C m-2 d-1) over the shelf prior to our survey, (2) freshwater dilution by river runoff and ice melt, and (3) the presence of cold surface waters offshore. Only the Mackenzie River delta and localized shelf areas directly affected by upwelling were identified as substantial sources of CO2 to the atmosphere (> 10 mmol C m-2 d-1). Daily PP rates were generally state.

  9. Modeling plankton ecosystem functioning and nitrogen fluxes in the oligotrophic waters of the Beaufort Sea, Arctic Ocean: a focus on light-driven processes

    Directory of Open Access Journals (Sweden)

    V. Le Fouest

    2013-07-01

    Full Text Available The Arctic Ocean (AO undergoes profound changes of its physical and biotic environments due to climate change. In some areas of the Beaufort Sea, the stronger haline stratification observed in summer alters the plankton ecosystem structure, functioning and productivity, promoting oligotrophy. A one-dimension (1-D physical–biological coupled model based on the large multiparametric database of the Malina project in the Beaufort Sea was used (i to infer the plankton ecosystem functioning and related nitrogen fluxes and (ii to assess the model sensitivity to key light-driven processes involved in nutrient recycling and phytoplankton growth. The coupled model suggested that ammonium photochemically produced from photosensitive dissolved organic nitrogen (i.e., photoammonification process was a necessary nitrogen source to achieve the observed levels of microbial biomass and production. Photoammonification directly and indirectly (by stimulating the microbial food web activity contributed to 70% and 18.5% of the 0–10 m and whole water column, respectively, simulated primary production (respectively 66% and 16% for the bacterial production. The model also suggested that variable carbon to chlorophyll ratios were required to simulate the observed herbivorous versus microbial food web competition and realistic nitrogen fluxes in the Beaufort Sea oligotrophic waters. In face of accelerating Arctic warming, more attention should be paid in the future to the mechanistic processes involved in food webs and functional group competition, nutrient recycling and primary production in poorly productive waters of the AO, as they are expected to expand rapidly.

  10. Prevalence and spatio-temporal variation of an alopecia syndrome in polar bears (Ursus maritimus) of the southern Beaufort Sea.

    Science.gov (United States)

    Atwood, Todd; Peacock, Elizabeth; Burek-Huntington, Kathy; Shearn-Bochsler, Valerie; Bodenstein, Barbara; Beckmen, Kimberlee; Durner, George

    2015-01-01

    Alopecia (hair loss) has been observed in several marine mammal species and has potential energetic consequences for sustaining a normal core body temperature, especially for Arctic marine mammals routinely exposed to harsh environmental conditions. Polar bears (Ursus maritimus) rely on a thick layer of adipose tissue and a dense pelage to ameliorate convective heat loss while moving between sea ice and open water. From 1998 to 2012, we observed an alopecia syndrome in polar bears from the southern Beaufort Sea of Alaska that presented as bilaterally asymmetrical loss of guard hairs and thinning of the undercoat around the head, neck, and shoulders, which, in severe cases, was accompanied by exudation and crusted skin lesions. Alopecia was observed in 49 (3.45%) of the bears sampled during 1,421 captures, and the apparent prevalence varied by years with peaks occurring in 1999 (16%) and 2012 (28%). The probability that a bear had alopecia was greatest for subadults and for bears captured in the Prudhoe Bay region, and alopecic individuals had a lower body condition score than unaffected individuals. The cause of the syndrome remains unknown and future work should focus on identifying the causative agent and potential effects on population vital rates. PMID:25375943

  11. Genetic variation, relatedness, and effective population size of polar bears (Ursus maritimus) in the southern Beaufort Sea, Alaska

    Science.gov (United States)

    Cronin, M.A.; Amstrup, Steven C.; Talbot, S.L.; Sage, G.K.; Amstrup, K.S.

    2009-01-01

    Polar bears (Ursus maritimus) are unique among bears in that they are adapted to the Arctic sea ice environment. Genetic data are useful for understanding their evolution and can contribute to management. We assessed parentage and relatedness of polar bears in the southern Beaufort Sea, Alaska, with genetic data and field observations of age, sex, and mother-offspring and sibling relationships. Genotypes at 14 microsatellite DNA loci for 226 bears indicate that genetic variation is comparable to other populations of polar bears with mean number of alleles per locus of 7.9 and observed and expected heterozygosity of 0.71. The genetic data verified 60 field-identified mother-offspring pairs and identified 10 additional mother-cub pairs and 48 father-offspring pairs. The entire sample of related and unrelated bears had a mean pairwise relatedness index (rxy) of approximately zero, parent-offspring and siblings had rxy of approximately 0.5, and 5.2% of the samples had rxy values within the range expected for parent-offspring. Effective population size (Ne = 277) and the ratio of Ne to total population size (Ne/N = 0.182) were estimated from the numbers of reproducing males and females. Ne estimates with genetic methods gave variable results. Our results verify and expand field data on reproduction by females and provide new data on reproduction by males and estimates of relatedness and Ne in a polar bear population. ?? The American Genetic Association. 2009. All rights reserved.

  12. Aerial surveys of endangered whales in the Alaskan Chukchi and western Beaufort Seas, 1990. Final report, Oct-Nov 90

    International Nuclear Information System (INIS)

    In keeping with the National Environmental Policy Act (1969), the Marine Mammal Protection Act (1972) and the Endangered Species Act (1973), the OCS Lands Act Amendments (1978) established a management policy that included studies in OCS lease sale areas to ascertain potential environmental impacts of oil and gas development on OCS marine coastal environments. The Minerals Management Service (MMS) is the agency responsible for these studies and for the leasing of submerged Federal lands. The report summarizes the 1990 investigations of the distribution, abundance, migration, behavior and habitat relationships of endangered whales in the Alaskan Chukchi and western Beaufort Seas (hereafter, study area); 1990 was the second of a three year (1989-91) study. The Bering Sea stock of bowhead whales (Balaena mysticetus) was the principal species studied, with incidental sightings of all other marine mammals routinely recorded. The 1990 season was compromised by circumstances that restricted the availability of the survey aircraft (Grumman Goose, model G21G) to the period 26 October - 7 November; opportunistic surveys were flown in the study area from 3-25 October. In 1990, there were 14 sightings of 19 bowheads from 9-29 October; 5 whales, including 2 calves, were seen north of the study area. One gray whale, 110 belukhas and 53 polar bears were also seen. Over nine survey seasons (1982-90), there were 240 sightings of 520 bowhead whales and 148 sightings of 398 gray whales

  13. Change in the Beaufort Sea ecosystem: Diverging trends in body condition and/or production in five marine vertebrate species

    Science.gov (United States)

    Harwood, L. A.; Smith, T. G.; George, J. C.; Sandstrom, S. J.; Walkusz, W.; Divoky, G. J.

    2015-08-01

    Studies of the body condition of five marine vertebrate predators in the Beaufort Sea, conducted independently during the past 2-4 decades, suggest each has been affected by biophysical changes in the marine ecosystem. We summarize a temporal trend of increasing body condition in two species (bowhead whale subadults, Arctic char), in both cases influenced by the extent and persistence of annual sea ice. Three other species (ringed seal, beluga, black guillemot chicks), consumers with a dietary preference for Arctic cod, experienced declines in condition, growth and/or production during the same time period. The proximate causes of these observed changes remain unknown, but may reflect an upward trend in secondary productivity, and a concurrent downward trend in the availability of forage fishes, such as the preferred Arctic cod. To further our understanding of these apparent ecosystem shifts, we urge the use of multiple marine vertebrate species in the design of biophysical sampling studies to identify causes of these changes. Continued long-term, standardized monitoring of vertebrate body condition should be paired with concurrent direct (stomach contents) or indirect (isotopes, fatty acids) monitoring of diet, detailed study of movements and seasonal ranges to establish and refine baselines, and identification of critical habitats of the marine vertebrates being monitored. This would be coordinated with biophysical and oceanographic sampling, at spatial and temporal scales, and geographic locations, that are relevant to the home range, critical habitats and prey of the vertebrate indicator species showing changes in condition and related parameters.

  14. Prevalence and spatio-temporal variation of an alopecia syndrome in polar bears (Ursus maritimus) of the southern Beaufort Sea

    Science.gov (United States)

    Atwood, Todd C.; Peacock, Elizabeth; Burek, K.A.; Shearn-Bochsler, Valerie I.; Bodenstein, Barbara L.; Beckmen, Kimberlee B.; Durner, George M.

    2015-01-01

    Alopecia (hair loss) has been observed in several marine mammal species and has potential energetic consequences for sustaining a normal core body temperature, especially for Arctic marine mammals routinely exposed to harsh environmental conditions. Polar bears (Ursus maritimus) rely on a thick layer of adipose tissue and a dense pelage to ameliorate convective heat loss while moving between sea ice and open water. From 1998 to 2012, we observed an alopecia syndrome in polar bears from the southern Beaufort Sea of Alaska that presented as bilaterally asymmetrical loss of guard hairs and thinning of the undercoat around the head, neck, and shoulders, which, in severe cases, was accompanied by exudation and crusted skin lesions. Alopecia was observed in 49 (3.45%) of the bears sampled during 1,421 captures, and the apparent prevalence varied by years with peaks occurring in 1999 (16%) and 2012 (28%). The probability that a bear had alopecia was greatest for subadults and for bears captured in the Prudhoe Bay region, and alopecic individuals had a lower body condition score than unaffected individuals. The cause of the syndrome remains unknown and future work should focus on identifying the causative agent and potential effects on population vital rates.

  15. Polar bears in the southern Beaufort Sea III: Stature, mass, and cub recruitment in relationship to time and sea ice extent between 1982 and 2006

    Science.gov (United States)

    Rode, Karyn D.; Amstrup, Steven C.; Regehr, Eric V.

    2007-01-01

    Changes in individual stature and body mass can affect reproduction and survival and have been shown to be early indicators of changes in status and trends of polar bear populations. We recorded body length, skull size, and mass of polar bears (Ursus maritimus) during capture/recapture studies conducted in the southern Beaufort Sea of Alaska (SB) between 1982 and 2006. We calculated a body condition index (BCI) which reflects trends in mass relative to length. We also recorded the number of dependent young accompanying females in the spring and fall as an indicator of cub recruitment. Previous work suggested stature of some sex and age classes of bears in the SB had changed between early and latter portions of this study but did not investigate trends in or causes of those changes. Here, we investigate whether these measurements changed over time or in relation to sea ice extent. Because our study required bears to be repeatedly immobilized and captured, we tested whether frequency of capture could have affected these measurements. Mass, length, skull size, and BCI of growing males (aged 3-10), mass and skull size of cubs-of-the year, and the number of yearlings per female in the spring and fall were all positively related to the percent of days in which sea ice covered the continental shelf. Skull sizes and/or lengths of adult and subadult males and females decreased over time during the study. Adult body mass was not related to sea ice cover and did not show a trend with time. BCI of adult females exhibited a positive trend over time reflecting a decline in length without a parallel trend in mass. Though cub production increased over time, the number of cubs-of-the-year (COYs) per female in the fall and yearlings per female in the spring declined suggesting reduced cub survival. Bears with prior capture history were either larger or similar in stature and mass to bears captured for the first time, indicating that research activities did not influence trends in

  16. Tectonique dans la région de la mer de Beaufort (Arctique canadien (résumé Tectonism in the Beaufort Sea - Region of Arctic Canada (Abstract

    Directory of Open Access Journals (Sweden)

    Mroszczak W. E.

    2006-10-01

    Full Text Available Le delta de la Mackenzie et la mer de Beaufort qui en sont encore au début de l'exploration, peuvent devenir une région pétrolière majeure dans les années 1980. Ce vaste bassin tertiaire est situé dans un environnement arctique ; il a demandé et nécessitera dans l'avenir de nouvelles technologies pour développer et produire les hydrocarbures si l'exploration est couronnée de succès. L'exploration pour l'huile et le gaz a été active dans cette région depuis 1965 bien que les facteurs climatiques et économiques aient eu tendance à freiner cette exploration, particulièrement en mer. L'auteur présente un bref historique des recherches comprenant les derniers résultats des sondage dans la mer de Beaufort forés par Dome Petroleum et ses partenaires. On discute aussi l'origine des structures en mer, en commentant les données sismiques. La structuration est considérée comme le résultat d'une sédimentation rapide de clastiques au Tertiaire dans un bassin dont le substratum serait formé d'une épaisse série d'argiles sous-compactées d'âge jurassique ou crétacé. The Mackenzie Delta and offshore Beaufort Sea Region which is at a very early stage of exploration, may become a major source of hydrocarbons in the 1980's This large Tertiary basin is situated in an Arctic environment and has required, and will require in the future, new technology to develop and produce hydrocarbons if exploration is successful. Exploration for oil and gas has been active in the area since 1965 with climatic and economic factors contributing ta a slow pace of exploration, particularly in the offshore area. A brief history of exploration with and update of the latest results of drilling in the Beaufort by Dome Petroleum and its partners is presented. Using seismic data, the genesis of structures found in the offshore area is discussed. These are believed to be the result of rapid Tertiary clastic deposition in a basin underlain by a thick section of

  17. Habitat use and foraging patterns of molting male Long-tailed Ducks in lagoons of the central Beaufort Sea, Alaska

    Science.gov (United States)

    Flint, Paul L.; Reed, John; Deborah Lacroix; Richard Lanctot

    2016-01-01

    From mid-July through September, 10 000 to 30 000 Long-tailed Ducks (Clangula hyemalis) use the lagoon systems of the central Beaufort Sea for remigial molt. Little is known about their foraging behavior and patterns of habitat use during this flightless period. We used radio transmitters to track male Long-tailed Ducks through the molt period from 2000 to 2002 in three lagoons: one adjacent to industrial oil field development and activity and two in areas without industrial activity. We found that an index to time spent foraging generally increased through the molt period. Foraging, habitat use, and home range size showed similar patterns, but those patterns were highly variable among lagoons and across years. Even with continuous daylight during the study period, birds tended to use offshore areas during the day for feeding and roosted in protected nearshore waters at night. We suspect that variability in behaviors associated with foraging, habitat use, and home range size are likely influenced by availability of invertebrate prey. Proximity to oil field activity did not appear to affect foraging behaviors of molting Long-tailed Ducks.

  18. Wildlife and wildlife habitat restoration and compensation in the event of an oil spill in the Beaufort Sea

    International Nuclear Information System (INIS)

    A procedure for estimating the potential costs of a worst-case scenario for a Beaufort Sea oil spill has been developed by applying assessments of the vulnerability and sensitivity of valued wildlife species to oil, an evaluation of practicability of restoration options, and estimates of the costs of implementing specific measures to aid in the restoration of wildlife species and their habitat. The procedure was developed and tested using valued wildlife species and elements of selected worst-case oil spill scenarios. Proponent use of the procedure in a project-specific application will demand certain information prerequisites, including a project-specific oil spill scenario, an assessment of the potential impacts on wildlife and habitat, and the predicted effectiveness of countermeasures and cleanup. Total compensation costs that account for potential loss of harvest of wildlife in the event of a worst-case oil spill were estimated to be nearly $12.2 million. Recommendations were also made with respect to wildlife and wildlife habitat restoration, as well as with respect to compensation issues. 103 refs., 4 figs., 4 tabs

  19. Genetic variation, relatedness, and effective population size of polar bears (Ursus maritimus) in the southern Beaufort Sea, Alaska.

    Science.gov (United States)

    Cronin, Matthew A; Amstrup, Steven C; Talbot, Sandra L; Sage, George K; Amstrup, Kristin S

    2009-01-01

    Polar bears (Ursus maritimus) are unique among bears in that they are adapted to the Arctic sea ice environment. Genetic data are useful for understanding their evolution and can contribute to management. We assessed parentage and relatedness of polar bears in the southern Beaufort Sea, Alaska, with genetic data and field observations of age, sex, and mother-offspring and sibling relationships. Genotypes at 14 microsatellite DNA loci for 226 bears indicate that genetic variation is comparable to other populations of polar bears with mean number of alleles per locus of 7.9 and observed and expected heterozygosity of 0.71. The genetic data verified 60 field-identified mother-offspring pairs and identified 10 additional mother-cub pairs and 48 father-offspring pairs. The entire sample of related and unrelated bears had a mean pairwise relatedness index (r(xy)) of approximately zero, parent-offspring and siblings had r(xy) of approximately 0.5, and 5.2% of the samples had r(xy) values within the range expected for parent-offspring. Effective population size (N(e) = 277) and the ratio of N(e) to total population size (N(e)/N = 0.182) were estimated from the numbers of reproducing males and females. N(e) estimates with genetic methods gave variable results. Our results verify and expand field data on reproduction by females and provide new data on reproduction by males and estimates of relatedness and N(e) in a polar bear population. PMID:19633212

  20. Seasonal spatial patterns in seabird and marine mammal distribution in the eastern Chukchi and western Beaufort seas: Identifying biologically important pelagic areas

    Science.gov (United States)

    Kuletz, Kathy J.; Ferguson, Megan C.; Hurley, Brendan; Gall, Adrian E.; Labunski, Elizabeth A.; Morgan, Tawna C.

    2015-08-01

    The Chukchi and Beaufort seas are undergoing rapid climate change and increased human activity. Conservation efforts for upper trophic level predators such as seabirds and marine mammals require information on species' distributions and identification of important marine areas. Here we describe broad-scale distributions of seabirds and marine mammals. We examined spatial patterns of relative abundance of seabirds and marine mammals in the eastern Chukchi and western Beaufort seas during summer (15 June-31 August) and fall (1 September-20 November) from 2007 to 2012. We summarized 49,206 km of shipboard surveys for seabirds and 183,157 km of aerial surveys for marine mammals into a grid of 40-km × 40-km cells. We used Getis-Ord Gi∗ hotspot analysis to test for cells with higher relative abundance than expected when compared to all cells within the study area. We identified cells representing single species and taxonomic group hotspots, cells representing hotspots for multiple species, and cells representing hotspots for both seabirds and marine mammals. The locations of hotspots varied among species but often were located near underwater canyons or over continental shelf features and slopes. Hotspots for seabirds, walrus, and gray whales occurred primarily in the Chukchi Sea. Hotspots for bowhead whales and other pinnipeds (i.e., seals) occurred near Barrow Canyon and along the Beaufort Sea shelf and slope. Hotspots for belugas occurred in both the Chukchi and Beaufort seas. There were three hotspots shared by both seabirds and marine mammals in summer: off Wainwright in the eastern Chukchi Sea, south of Hanna Shoal, and at the mouth of Barrow Canyon. In fall, the only identified shared hotspot occurred at the mouth of Barrow Canyon. Shared hotspots are characterized by strong fronts caused by upwelling and currents, and these areas can have high densities of euphausiids in summer and fall. Due to the high relative abundance of animals and diversity of taxa

  1. Velocity models and images using full waveform inversion and reverse time migration for the offshore permafrost in the Canadian shelf of Beaufort Sea, Arctic

    Science.gov (United States)

    Kang, S. G.; Hong, J. K.; Jin, Y. K.; Kim, S.; Kim, Y. G.; Dallimore, S.; Riedel, M.; Shin, C.

    2015-12-01

    During Expedition ARA05C (from Aug 26 to Sep 19, 2014) on the Korean icebreaker RV ARAON, the multi-channel seismic (MCS) data were acquired on the outer shelf and slope of the Canadian Beaufort Sea to investigate distribution and internal geological structures of the offshore ice-bonded permafrost and gas hydrates, totaling 998 km L-km with 19,962 shots. The MCS data were recorded using a 1500 m long solid-type streamer with 120 channels. Shot and group spacing were 50 m and 12.5 m, respectively. Most MCS survey lines were designed perpendicular and parallel to the strike of the shelf break. Ice-bonded permafrost or ice-bearing sediments are widely distributed under the Beaufort Sea shelf, which have formed during periods of lower sea level when portions of the shelf less than ~100m water depth were an emergent coastal plain exposed to very cold surface. The seismic P-wave velocity is an important geophysical parameter for identifying the distribution of ice-bonded permafrost with high velocity in this area. Recently, full waveform inversion (FWI) and reverse time migration (RTM) are commonly used to delineate detailed seismic velocity information and seismic image of geological structures. FWI is a data fitting procedure based on wave field modeling and numerical analysis to extract quantitative geophysical parameters such as P-, S-wave velocities and density from seismic data. RTM based on 2-way wave equation is a useful technique to construct accurate seismic image with amplitude preserving of field data. In this study, we suggest two-dimensional P-wave velocity model (Figure.1) using the FWI algorithm to delineate the top and bottom boundaries of ice-bonded permafrost in the Canadian shelf of Beaufort Sea. In addition, we construct amplitude preserving migrated seismic image using RTM to interpret the geological history involved with the evolution of permafrost.

  2. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from underway - surface observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from the XUE LONG in the Arctic Ocean, Beaufort Sea and Bering Sea from 2008-07-30 to 2008-09-11 (NODC Accession 0109932)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0109932 includes chemical, meteorological, physical and underway - surface data collected from XUE LONG in the Arctic Ocean, Beaufort Sea and Bering...

  3. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, PAR Sensor and other instruments from the HEALY in the Arctic Ocean, Beaufort Sea and Bering Sea from 2004-05-15 to 2004-06-23 (NODC Accession 0115592)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0115592 includes biological, chemical, discrete sample, physical and profile data collected from HEALY in the Arctic Ocean, Beaufort Sea and Bering...

  4. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the HEALY in the Arctic Ocean, Beaufort Sea and Bering Sea from 2004-07-18 to 2004-08-26 (NODC Accession 0115707)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0115707 includes biological, chemical, discrete sample, physical and profile data collected from HEALY in the Arctic Ocean, Beaufort Sea and Bering...

  5. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the LOUIS S. ST. LAURENT in the Arctic Ocean, Beaufort Sea and North Greenland Sea from 1994-07-24 to 1994-09-01 (NODC Accession 0113983)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113983 includes chemical, discrete sample, physical and profile data collected from LOUIS S. ST. LAURENT in the Arctic Ocean, Beaufort Sea and North...

  6. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the HEALY in the Arctic Ocean, Beaufort Sea and Bering Sea from 2002-07-18 to 2002-08-21 (NODC Accession 0113953)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113953 includes biological, chemical, discrete sample, physical and profile data collected from HEALY in the Arctic Ocean, Beaufort Sea and Bering...

  7. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, PAR Sensor and other instruments from the HEALY in the Arctic Ocean, Beaufort Sea and Bering Sea from 2002-05-05 to 2002-06-15 (NODC Accession 0113952)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113952 includes biological, chemical, discrete sample, physical and profile data collected from HEALY in the Arctic Ocean, Beaufort Sea and Bering...

  8. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from HEALY in the Arctic Ocean, Beaufort Sea and others from 2014-05-05 to 2014-08-30 (NCEI Accession 0144350)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144350 includes Surface underway data collected from HEALY in the Arctic Ocean, Beaufort Sea, Bering Sea, Coastal Waters of SE Alaska, Gulf of...

  9. An oilspill risk analysis for the Beaufort Sea, Alaska (proposed sale 71)outer continental shelf lease area

    Science.gov (United States)

    Samuels, W.B.; Hopkins, Dorothy; Lanfear, K.J.

    1981-01-01

    An oilspill risk analysis was conducted to determine the relative environmental hazards of developing oil in different regions of the Beaufort Sea, Alaska, (Proposed Sale 71) Outer Continental Shelf (OCS) lease area. The probability of spill occurrences, likely movement of oil slicks, and locations of resources vulnerable to spilled oil were analyzed. The model predicted movement of the center of spill mass and estimated the times between spill occurrence and contact with various resources, to allow a qualitative assessment of oil characteristics at the time of contact; no direct computation was made of weathering and cleanup. The model also assumed that any oil spilled under ice would remain in place, unchanged, until spring breakup. Ice movements, or travel of oil under ice, if occurring, would affect the results in a manner not directly predictable at this time. The combined results of spill occurrence and spill movement predictions yielded estimates of the overall risks associated with development of the proposed lease area. Assuming that oil exists in the lease area (a 99.3-percent chance) it is estimated that the leasing of the tracts proposed for OCS Sale 71 will result in an expected 9.2 oilspills (of 1,000 barrels or larger) over the lease lifetime of 25 years. This estimate is based on historic oilspill accident data for platforms and pipelines on the U.S. OCS (Gulf of Mexico and California). The estimated probability that land will be contacted by one or more oilspills (of 1,000 barrels or larger) that have been at sea less than 30 days (not counting any time trapped under ice) is greater than 99.5 percent. If oilspill accident data for Prudhoe Bay, Alaska, is used in the analysis, it is estimated that 5.6 oilspills (1,000 barrels or larger) will occur over the lease lifetime. The estimated probability that one or more oilspills (1,000 barrels or larger)will occur and contact land is99 percent. The results of a recent experimental cleanup operation for

  10. Assessing the potential impacts of declining Arctic sea ice cover on the photochemical degradation of dissolved organic matter in the Chukchi and Beaufort Seas

    Science.gov (United States)

    Logvinova, Christie L.; Frey, Karen E.; Mann, Paul J.; Stubbins, Aron; Spencer, Robert G. M.

    2015-11-01

    A warming and shifting climate in the Arctic has led to significant declines in sea ice over the last several decades. Although these changes in sea ice cover are well documented, large uncertainties remain in how associated increases in solar radiation transmitted to the underlying ocean water column will impact heating, biological, and biogeochemical processes in the Arctic Ocean. In this study, six under-ice marine, two ice-free marine, and two ice-free terrestrially influenced water samples were irradiated using a solar simulator for 72 h (representing ~10 days of ambient sunlight) to investigate dissolved organic matter (DOM) dynamics from the Chukchi and Beaufort Seas. Solar irradiation caused chromophoric DOM (CDOM) light absorption at 254 nm to decrease by 48 to 63%. An overall loss in total DOM fluorescence intensity was also observed at the end of all experiments, and each of six components identified by parallel factor (PARAFAC) analysis was shown to be photoreactive in at least one experiment. Fluorescent DOM (FDOM) also indicated that the majority of DOM in under-ice and ice-free marine waters was likely algal-derived. Measurable changes in dissolved organic carbon (DOC) were only observed for sites influenced by riverine runoff. Losses of CDOM absorbance at shorter wavelengths suggest that the beneficial UV protection currently received by marine organisms may decline with the increased light transmittance associated with sea ice melt ponding and overall reductions of sea ice. Our FDOM analyses demonstrate that DOM irrespective of source was susceptible to photobleaching. Additionally, our findings suggest that photodegradation of CDOM in under-ice waters is not currently a significant source of carbon dioxide (CO2) (i.e., we did not observe systematic DOC loss). However, increases in primary production and terrestrial freshwater export expected under future climate change scenarios may cause an increase in CDOM quantity and shift in quality

  11. Distributions of surface water CO2 and air-sea flux of CO2 in coastal regions of the Canadian Beaufort Sea in late summer

    Directory of Open Access Journals (Sweden)

    M. Itoh

    2008-12-01

    Full Text Available To quantify the air-sea flux of CO2 in a high-latitude coastal region, we conducted shipboard observations of atmospheric and surface water partial pressures of CO2 (pCO2 and total dissolved inorganic carbon (TCO2 in the Canadian Beaufort Sea (150° W–127° W; 69° N–73° N in late summer 2000 and 2002. Surface water pCO2 was lower than atmospheric pCO2 (2000, 361.0 μatm; 2002, 364.7 μatm, and ranged from 250 to 344 μatm. Accordingly, ΔpCO2, which is the driving force of the air-sea exchange of CO2 and is calculated from differences in pCO2 between the sea surface and the overlying air, was generally negative (potential sink for atmospheric CO2, although positive ΔpCO2 values (source were also found locally. Distributions of surface water pCO2, as well as those of ΔpCO2 and CO2 flux, were controlled mainly by water mixing related to river discharge. The air-sea fluxes of CO2 were −15.0 and −16.8 mmol m−2 d−1 on average in 2000 and 2002, respectively, implying that the area acted as a moderate sink for atmospheric CO2. The air-to-sea net CO2 flux in an extended area of the western Arctic Ocean (411 000 km2 during the ice-free season (=100 days was calculated as 10.2±7.7 mmol m−2 d−1, equivalent to a regional CO2 sink of 5.0±3.8 Tg C. The estimated buffer factor was 1.5, indicating that the area is a high-capacity CO2 sink. These CO2 flux estimates will need to be revised because they probably include a bias due to the vertical gradients of physical and chemical properties characteristic in the region, which have not yet been adequately considered.

  12. Active seafloor gas vents on the Shelf and upper Slope in Canadian Beaufort Sea

    Science.gov (United States)

    Paull, C. K.; Dallimore, S. R.; Hughes Clarke, J. E.; Blasco, S.; Taylor, A. E.; Melling, H.; Vagle, S.; Conway, K.; Riedel, M.; Lundsten, E.; Gwiazda, R.

    2012-12-01

    In the Canadian Arctic shelf and upper slope, a thermal disturbance caused by sea level rise at the end of the last glacial period, is still propagating into the subsurface and heating shelf sediments, where submerged terrestrial permafrost and gas hydrate, and marine gas hydrate are believed to occur in close proximity. On-going studies show evidence of gas venting in association with three distinct environments: Pingo-Like-Features (PLF) on the mid-shelf; along the shelf edge near the 100m contour; and ~1 km wide circular topographic features on the upper continental slope. Observations with a Remotely Operated Vehicle (ROV) show that methane is venting vigorously over point sources on the PLF's on the mid-shelf, and diffusely along the shelf edge. The stable isotopic composition of methane emanating from these environments indicates a microbial origin for the venting gas. Their negligible radiocarbon content indicates a geological source, as opposed to methangenisis associated with modern sediments. This is consistent with the change in the thermal regime produced by the last transgression. During glacial periods lower sea level exposed the current shelf to frigid sub-aerial temperatures. As a result, some areas of the shelf are underlain by >600m of ice-bonded permafrost with the base of methane hydrate stability at >1000m depths. The marine transgression imposed a change in mean annual surface temperature from -15°C or lower, to mean annual sea bottom temperatures near 0°C. The thermal disturbance is still propagating into the subsurface, stimulating the decomposition of both terrestrial permafrost and gas hydrate at depth and liberating methane. The PLF vents are believed to be sourced from the top of the gas hydrate stability field, while the gas emanating along the shelf edge can be from the decomposition of gas trapped in the permafrost or gas-hydrate underneath the continental shelf. The occurrence of water column flares over the distinctive circular

  13. Multivariate benthic ecosystem functioning in the Arctic – benthic fluxes explained by environmental parameters in the southeastern Beaufort Sea

    Directory of Open Access Journals (Sweden)

    H. Link

    2013-09-01

    Full Text Available The effects of climate change on Arctic marine ecosystems and their biogeochemical cycles are difficult to predict given the complex physical, biological and chemical interactions among the ecosystem components. We studied benthic biogeochemical fluxes in the Arctic and the influence of short-term (seasonal to annual, long-term (annual to decadal and other environmental variability on their spatial distribution to provide a baseline for estimates of the impact of future changes. In summer 2009, we measured fluxes of dissolved oxygen, nitrate, nitrite, ammonia, soluble reactive phosphate and silicic acid at the sediment–water interface at eight sites in the southeastern Beaufort Sea at water depths from 45 to 580 m. The spatial pattern of the measured benthic boundary fluxes was heterogeneous. Multivariate analysis of flux data showed that no single or reduced combination of fluxes could explain the majority of spatial variation, indicating that oxygen flux is not representative of other nutrient sink–source dynamics. We tested the influence of eight environmental parameters on single benthic fluxes. Short-term environmental parameters (sinking flux of particulate organic carbon above the bottom, sediment surface Chl a were most important for explaining oxygen, ammonium and nitrate fluxes. Long-term parameters (porosity, surface manganese and iron concentration, bottom water oxygen concentrations together with δ13Corg signature explained most of the spatial variation in phosphate, nitrate and nitrite fluxes. Variation in pigments at the sediment surface was most important to explain variation in fluxes of silicic acid. In a model including all fluxes synchronously, the overall spatial distribution could be best explained (57% by the combination of sediment Chl a, phaeopigments, δ13Corg, surficial manganese and bottom water oxygen concentration. We conclude that it is necessary to consider long-term environmental variability along with

  14. k283ar.m77t - MGD77 data file for Geophysical data from field activity K-2-83-AR in Arctic and Beaufort Sea, Alaska from 08/05/1983 to 08/22/1983

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Single-beam bathymetry data along with DGPS navigation data was collected as part of field activity K-2-83-AR in Arctic and Beaufort Sea, Alaska from 08/05/1983 to...

  15. A 50% increase in the amount of terrestrial particles delivered by the Mackenzie River into the Beaufort Sea (Canadian Arctic Ocean over the last 10 years

    Directory of Open Access Journals (Sweden)

    D. Doxaran

    2015-01-01

    Full Text Available Global warming has a significant impact at the regional scale on the Arctic Ocean and surrounding coastal zones (i.e., Alaska, Canada, Greenland, Norway and Russia. The recent increase in air temperature has resulted in increased precipitations along the drainage basins of Arctic Rivers. It has also directly impacted land and seawater temperatures with the consequence of melting the permafrost and sea-ice. An increase in freshwater discharge by main Arctic rivers has been clearly identified in time series of field observations. The freshwater discharge of the Mackenzie River has increased by 25% since 2003. This may have increased the mobilization and transport of various dissolved and particulate substances, including organic carbon, as well as their export to the ocean. The release from land to the ocean of such organic material, which was sequestered as frozen since the last glacial maximum, may significantly impact the Arctic Ocean carbon cycle as well as marine ecosystems. In this study we use 11 years of ocean-colour satellite data and field observations collected in 2009 to estimate the amount of terrestrial suspended solids and particulate organic carbon delivered by the Mackenzie River into the Beaufort Sea (Arctic Ocean. Our results show that during the summer period the concentration of suspended solids at the river mouth, in the delta zone and in the river plume has increased by 46, 71 and 33%, respectively, since 2003. Combined with the variations observed in the freshwater discharge, this corresponds to a more than 50% increase in the particulate (terrestrial suspended particles and organic carbon export from the Mackenzie River into the Beaufort Sea.

  16. A 50 % increase in the mass of terrestrial particles delivered by the Mackenzie River into the Beaufort Sea (Canadian Arctic Ocean) over the last 10 years

    Science.gov (United States)

    Doxaran, D.; Devred, E.; Babin, M.

    2015-06-01

    Global warming has a significant impact on the regional scale on the Arctic Ocean and surrounding coastal zones (i.e., Alaska, Canada, Greenland, Norway and Russia). The recent increase in air temperature has resulted in increased precipitation along the drainage basins of Arctic rivers. It has also directly impacted land and seawater temperatures with the consequence of melting permafrost and sea ice. An increase in freshwater discharge by main Arctic rivers has been clearly identified in time series of field observations. The freshwater discharge of the Mackenzie River has increased by 25% since 2003. This may have increased the mobilization and transport of various dissolved and particulate substances, including organic carbon, as well as their export to the ocean. The release from land to the ocean of such organic material, which has been sequestered in a frozen state since the Last Glacial Maximum, may significantly impact the Arctic Ocean carbon cycle as well as marine ecosystems. In this study we use 11 years of ocean color satellite data and field observations collected in 2009 to estimate the mass of terrestrial suspended solids and particulate organic carbon delivered by the Mackenzie River into the Beaufort Sea (Arctic Ocean). Our results show that during the summer period, the concentration of suspended solids at the river mouth, in the delta zone and in the river plume has increased by 46, 71 and 33%, respectively, since 2003. Combined with the variations observed in the freshwater discharge, this corresponds to a more than 50% increase in the particulate (terrestrial suspended particles and organic carbon) export from the Mackenzie River into the Beaufort Sea.

  17. A 50% increase in the amount of terrestrial particles delivered by the Mackenzie River into the Beaufort Sea (Canadian Arctic Ocean) over the last 10 years

    Science.gov (United States)

    Doxaran, D.; Devred, E.; Babin, M.

    2015-01-01

    Global warming has a significant impact at the regional scale on the Arctic Ocean and surrounding coastal zones (i.e., Alaska, Canada, Greenland, Norway and Russia). The recent increase in air temperature has resulted in increased precipitations along the drainage basins of Arctic Rivers. It has also directly impacted land and seawater temperatures with the consequence of melting the permafrost and sea-ice. An increase in freshwater discharge by main Arctic rivers has been clearly identified in time series of field observations. The freshwater discharge of the Mackenzie River has increased by 25% since 2003. This may have increased the mobilization and transport of various dissolved and particulate substances, including organic carbon, as well as their export to the ocean. The release from land to the ocean of such organic material, which was sequestered as frozen since the last glacial maximum, may significantly impact the Arctic Ocean carbon cycle as well as marine ecosystems. In this study we use 11 years of ocean-colour satellite data and field observations collected in 2009 to estimate the amount of terrestrial suspended solids and particulate organic carbon delivered by the Mackenzie River into the Beaufort Sea (Arctic Ocean). Our results show that during the summer period the concentration of suspended solids at the river mouth, in the delta zone and in the river plume has increased by 46, 71 and 33%, respectively, since 2003. Combined with the variations observed in the freshwater discharge, this corresponds to a more than 50% increase in the particulate (terrestrial suspended particles and organic carbon) export from the Mackenzie River into the Beaufort Sea.

  18. Synoptic evaluation of carbon cycling in Beaufort Sea during summer: contrasting river inputs, ecosystem metabolism and air–sea CO2 fluxes

    Directory of Open Access Journals (Sweden)

    A. Forest

    2013-10-01

    Full Text Available The accelerated decline in Arctic sea ice combined with an ongoing trend toward a more dynamic atmosphere is modifying carbon cycling in the Arctic Ocean. A critical issue is to understand how net community production (NCP; the balance between gross primary production and community respiration responds to changes and modulates air–sea CO2 fluxes. Using data collected as part of the ArcticNet-Malina 2009 expedition in southeastern Beaufort Sea (Arctic Ocean, we synthesize information on sea ice, wind, river, water column properties, metabolism of the planktonic food web, organic carbon fluxes and pools, as well as air–sea CO2 exchange, with the aim of identifying indices of ecosystem response to environmental changes. Data were analyzed to develop a non-steady-state carbon budget and an assessment of NCP against air–sea CO2 fluxes. The mean atmospheric forcing was a mild upwelling-favorable wind (~5 km h−1 blowing from the N-E and a decaying ice cover (2 with a mean uptake rate of −2.0 ± 3.3 mmol C m−2d−1. We attribute this discrepancy to: (1 elevated PP rates (>600 mg C m−2d−1 over the shelf prior to our survey, (2 freshwater dilution by river runoff and ice melt, and (3 the presence of cold surface waters offshore. Only the Mackenzie River delta and localized shelf areas directly affected by upwelling were identified as substantial sources of CO2 to the atmosphere (>10mmol C m−2d−1. Although generally −2d−1, daily PP rates cumulated to a total PP of ~437.6 × 103 t C, which was roughly twice higher than the organic carbon delivery by river inputs (~241.2 × 103 t C. Subsurface PP represented 37.4% of total PP for the whole area and as much as ~72.0% seaward of the shelf break. In the upper 100 m, bacteria dominated (54% total community respiration (~250 mg C m−2d−1, whereas protozoans, metazoans, and benthos, contributed to 24%, 10%, and 12%, respectively. The range of production-to-biomass ratios of bacteria was

  19. Marine animal sighting, benthic organism, and other data from aircraft and other platforms in the Bering and Beaufort Seas as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 19 August 1971 to 12 March 1983 (NODC Accession 8500273)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine animal sighting, benthic organism, and other data were collected from aircraft and other platforms in the Bering and Beaufort Seas from 19 August 1971 to 12...

  20. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the LOUIS S. ST. LAURENT in the Beaufort Sea and Northwest Passage from 1997-08-31 to 1997-09-16 (NODC Accession 0116061)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0116061 includes chemical, discrete sample, physical and profile data collected from LOUIS S. ST. LAURENT in the Beaufort Sea and Northwest Passage...

  1. Temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the HEALY in the Arctic Ocean and Beaufort Sea from 2003-09-11 to 2003-10-18 (NODC Accession 0115676)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0115676 includes biological, chemical, discrete sample, physical and profile data collected from HEALY in the Arctic Ocean and Beaufort Sea from...

  2. Temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the USCGC POLAR STAR in the Arctic Ocean and Beaufort Sea from 2002-07-15 to 2002-08-13 (NODC Accession 0115609)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0115609 includes chemical, discrete sample, physical and profile data collected from USCGC POLAR STAR in the Arctic Ocean and Beaufort Sea from...

  3. Temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the TYRO in the Arctic Ocean and Beaufort Sea from 1996-09-13 to 1996-10-28 (NODC Accession 0116717)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0116717 includes chemical, discrete sample, physical and profile data collected from TYRO in the Arctic Ocean and Beaufort Sea from 1996-09-13 to...

  4. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the LOUIS S. ST. LAURENT in the Arctic Ocean and Beaufort Sea from 1997-09-24 to 1997-10-15 (NODC Accession 0113984)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113984 includes chemical, discrete sample, physical and profile data collected from LOUIS S. ST. LAURENT in the Arctic Ocean and Beaufort Sea from...

  5. Temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the HEALY in the Arctic Ocean and Beaufort Sea from 2004-07-18 to 2004-08-26 (NODC Accession 0113548)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113548 includes biological, chemical, discrete sample, physical and profile data collected from HEALY in the Arctic Ocean and Beaufort Sea from...

  6. Marine mammal specimen and other data from the Beaufort Sea and other locations from the USCGC NORTHWIND and other platforms as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 01 January 1978 to 13 July 1979 (NODC Accession 8000431)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine mammal specimen and other data were collected in the Beaufort Sea and other locations from the USCGC NORTHWIND and other platforms from 01 January 1978 to 13...

  7. Marine mammal specimen and other data from the Beaufort Sea and other locations from the SURVEYOR and other platforms as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 25 January 1977 to 17 November 1977 (NODC Accession 7900339)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine mammal specimen and other data were collected in the Beaufort Sea from the SURVEYOR and other platforms from 25 January 1977 to 17 November 1977. Data were...

  8. UV/PAR radiation and DOM properties in surface coastal waters of the Canadian shelf of the Beaufort Sea during summer 2009

    Directory of Open Access Journals (Sweden)

    J. Para

    2013-04-01

    Full Text Available Surface waters from the Beaufort Sea in the Arctic Ocean were evaluated for dissolved organic carbon (DOC, and optical characteristics including UV (ultraviolet radiation and PAR (photosynthetically active radiation diffuse attenuation (Kd, and chromophoric and fluorescent dissolved organic matter (CDOM and FDOM as part of the MALINA field campaign (30 July to 27 August. Spectral absorption coefficients (aCDOM (350 nm (m−1 were significantly correlated to both diffuse attenuation coefficients (Kd in the UV-A and UV-B and to DOC concentrations. This indicates CDOM as the dominant attenuator of both UV and PAR solar radiation and suggests its use as an optical proxy for DOC concentrations in this region. While the Mackenzie input is the main driver of CDOM dynamics in low salinity waters, locally, primary production can create significant increases in CDOM. Extrapolating CDOM to DOC relationships, we estimate that ∼16% of the DOC in the Mackenzie River does not absorb radiation at 350 nm. The discharges of DOC and its chromophoric subset (CDOM by the Mackenzie River during the MALINA cruise are estimated as ∼0.22 TgC and 0.18 TgC, respectively. Three dissolved fluorescent components (C1–C3 were identified by fluorescence excitation/emission matrix spectroscopy (EEMS and parallel factor (PARAFAC analysis. Our results showed an aquatic dissolved organic matter (DOM component (C1, probably produced in the numerous lakes of the watershed, that co-dominated with a terrestrial humic-like component (C2 in the Mackenzie Delta Sector. This aquatic DOM could partially explain the high CDOM spectral slopes observed in the Beaufort Sea.

  9. The relationship between sea ice concentration and the spatio-temporal distribution of vocalizing bearded seals (Erignathus barbatus) in the Bering, Chukchi, and Beaufort Seas from 2008 to 2011

    Science.gov (United States)

    MacIntyre, Kalyn Q.; Stafford, Kathleen M.; Conn, Paul B.; Laidre, Kristin L.; Boveng, Peter L.

    2015-08-01

    Bearded seals (Erignathus barbatus) are widely distributed in the Arctic and sub-Arctic; the Beringia population is found throughout the Bering, Chukchi and Beaufort Seas (BCB). Bearded seals are highly vocal, using underwater calls to advertise their breeding condition and maintain aquatic territories. They are also closely associated with pack ice for reproductive activities, molting, and resting. Sea ice habitat for this species varies spatially and temporally throughout the year due to differences in underlying physical and oceanographic features across its range. To test the hypothesis that the vocal activity of bearded seals is related to variations in sea ice, passive acoustic data were collected from nine locations throughout the BCB from 2008 to 2011. Recording instruments sampled on varying duty cycles ranging from 20% to 100% of each hour, and recorded frequencies up to 8192 Hz. Spectrograms of acoustic data were analyzed manually to calculate the daily proportion of hours with bearded seal calls at each sampling location, and these call activity proportions were correlated with daily satellite-derived estimates of sea ice concentration. Bearded seals were vocally active nearly year-round in the Beaufort and Chukchi Seas with peak activity occurring from mid-March to late June during the mating season. The duration of call activity in the Bering Sea was shorter, lasting typically only five months, and peaked from mid-March to May at the northernmost recorders. In all areas, call activity was significantly correlated with higher sea ice concentrations (p losses in ice cover may negatively impact bearded seals, not just by loss of habitat but also by altering the behavioral ecology of the BCB population.

  10. Direct Observations of Heat and Salt Entrainment Fluxes Across the Base of the Ocean Mixing Layer Under Marginal Ice Conditions in the Beaufort Sea

    Science.gov (United States)

    Gallaher, S.; Stanton, T. P.; Shaw, W. J.

    2014-12-01

    Measurements of turbulent fluxes of heat and salt across the base of the upper ocean mixed layer in summer marginal ice zone conditions in the Beaufort Sea were made using two eddy-correlation flux sensors with a vertical separation of 6m mounted on a depth-controlled frame. A third flux sensor measured fluxes 2m below the ice. A 16 element thermistor string measured finescale thermal gradients while a high resolution ADCP measured current profiles every 20cm across the frame to resolve finescale shear. Every hour the frame was profiled between 2m and 60m depth then re-positioned to span the base of the active mixing layer, determined primarily from the density profile, allowing the surface mixed layer entrainment fluxes to be determined. A range of wind conditions allowed mixed layer entrainment fluxes to be compared with several bulk entrainment formulations based on surface friction velocity values and the density jump across the base of the surface mixing layer.

  11. U.S. Geological Survey Polar Bear Mark-Recapture Records, Alaska Portion of the Southern Beaufort Sea, 2001-2010

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data were collected by the U.S. Geological Survey, Alaska Science Center, Polar Bear Research Program as part of long-term research on the southern Beaufort...

  12. An evaluation of the science needs to inform decisions on Outer Continental Shelf energy development in the Chukchi and Beaufort Seas, Alaska

    Science.gov (United States)

    Holland-Bartels, Leslie; Pierce, Brenda

    2011-01-01

    The U. S. Geological Survey (USGS) was asked to conduct an initial, independent evaluation of the science needs that would inform the Administration's consideration of the right places and the right ways in which to develop oil and gas resources in the Arctic Outer Continental Shelf (OCS), particularly focused on the Beaufort and Chukchi Seas. Oil and gas potential is significant in Arctic Alaska. Beyond petroleum potential, this region supports unique fish and wildlife resources and ecosystems, and indigenous people who rely on these resources for subsistence. This report summarizes key existing scientific information and provides initial guidance of what new and (or) continued research could inform decision making. This report is presented in a series of topical chapters and various appendixes each written by a subset of the USGS OCS Team based on their areas of expertise. Three chapters (Chapters 2, 3, and 4) provide foundational information on geology; ecology and subsistence; and climate settings important to understanding the conditions pertinent to development in the Arctic OCS. These chapters are followed by three chapters that examine the scientific understanding, science gaps, and science sufficiency questions regarding oil-spill risk, response, and impact (Chapter 5), marine mammals and anthropogenic noise (Chapter 6), and cumulative impacts (Chapter 7). Lessons learned from the 1989 Exxon Valdez Oil Spill are included to identify valuable "pre-positioned" science and scientific approaches to improved response and reduced uncertainty in damage assessment and restoration efforts (appendix D). An appendix on Structured Decision Making (appendix C) is included to illustrate the value of such tools that go beyond, but incorporate, science in looking at what can/should be done about policy and implementation of Arctic development. The report provides a series of findings and recommendations for consideration developed during the independent examination of

  13. Effects of capturing and collaring on polar bears: findings from long-term research on the southern Beaufort Sea population

    Science.gov (United States)

    Rode, Karyn D.; Pagano, Anthony M.; Bromaghin, Jeffrey F.; Atwood, Todd C.; Durner, George M.; Simac, Kristin; Amstrup, Steven C.

    2014-01-01

    Context: The potential for research methods to affect wildlife is an increasing concern among both scientists and the public. This topic has a particular urgency for polar bears because additional research is needed to monitor and understand population responses to rapid loss of sea ice habitat.

  14. Megafauna recovered from a cold hydrocarbon seep in the deep Alaskan Beaufort Sea, including a new species of Axinus (Thracidae: Bivalvia: Mollusca)

    Science.gov (United States)

    Powell, C. L.; Valentich-Scott, P.; Lorenson, T. D.; Edwards, B. D.

    2011-12-01

    Several specimens of a new species of Axinus and a single well-worn gastropod columella provisionally assigned to the genus Neptunea (Buccinidae: Gastropoda: Mollusca) were recently recovered from at least two cores, the longest of which is 5.72 m long, from a large seafloor mound, informally named the Canning Seafloor Mound (CSM). The CSM is located at 2,530 m water depth on the Alaskan Beaufort Sea slope north of Camden Bay and is a fluid explosion feature containing methane hydrate and methane-saturated sediments overlying a folded and faulted deep basin. Only two modern species of Axinus are currently known. Axinus grandis (Verrill & Smith, 1885) is a northern Atlantic species and the recently described species, A. cascadiensis Oliver and Holmes (2007), is only known from Baby Bare Seamount, Cascadia Basin, northeastern Pacific Ocean. Common fragments, single valves, and a single articulated specimen represent this new Axinus species. These shells were distributed over nearly the entire length of the primary core. All specimens show wear and (or) dissolution. The age of these specimens is unknown and no living representatives were encountered. The genus Axinus has a fossil record back to the early Eocene in England and the Paleocene and Eocene in Egypt. Biogeographically the genus appears to have originated in the Tethys Sea and became established in the Atlantic Ocean during the Eocene, spreading across the Arctic Ocean in the late Tertiary. With the opening of the Bering Strait in the latest Miocene or early Pliocene the genus Axinus migrated southwest into the northeast Pacific. Interestingly, hydrocarbon seep deposits are also present on the adjacent North Slope of Alaska in the Marsh Anticline at Carter Creek, Camden Bay. These rocks, the Nuwok beds, contain abundant Thracidae bivalve of the genus Thracia, but not Axinus, however the rocks also represent cold seep deposits. These rocks have been variously dated from Oligocene to Pliocene and the exact age

  15. UV/PAR radiations and DOM properties in surface coastal waters of the Canadian shelf of the Beaufort Sea during summer 2009

    Directory of Open Access Journals (Sweden)

    J. Para

    2012-11-01

    Full Text Available Water masses from the Beaufort Sea in the Arctic Ocean were evaluated for dissolved organic carbon (DOC, and optical characteristics including UV and PAR diffuse attenuation (Kd, and chromophoric and fluorescent dissolved organic matter (CDOM and FDOM as part of the MALINA field campaign (30 July to 27 August. Even with relatively low mean daily solar radiation incident on the sea surface (0.12 ± 0.03, 8.46 ± 1.64 and 18.09 ± 4.20 kJ m−2 for UV-B (305 nm, UV-A (380 nm and PAR, respectively, we report significant light penetration with 10% irradiance depths (Z10% (λ reaching 9.5 m for 340 nm (UV-A radiation in the Eastern sector and 4.5 m in the Mackenzie River influenced area (Western sector. Spectral absorption coefficients (aCDOM (350 nm (m−1 were significantly correlated to both diffuse attenuation coefficients (Kd in the UV-A and UV-B and to DOC concentrations. This indicates CDOM as the dominant attenuator of UV solar radiation and suggests its use as an optical proxy for DOC concentrations in this region. Extrapolating CDOM to DOC relationships, we estimate that ~ 16% of the DOC in the Mackenzie River does not absorb radiation at 350 nm. DOC and CDOM discharges by the Mackenzie River during the MALINA Cruise are estimated as ~ 0.22 TgC and 0.18 TgC, respectively. Three dissolved fluorescent components (C1–C3 were identified by fluorescence Excitation/Emission Matrix Spectroscopy (EEMS and PARAFAC analysis. Our results showed an in-situ biological component (C1 that co-dominated with a terrestrial humic-like component (C2 in the Mackenzie Delta sector, whereas the protein-like (C3 component dominated in the saltiest waters of the North East sector.

  16. Studies of the inner shelf and coastal sedimentation environment of the Beaufort Sea from ERTS-A

    Science.gov (United States)

    Reimnitz, E. (Principal Investigator); Barnes, P. W.; Toimil, L. J.; Harden, D.

    1976-01-01

    The author has identified the following significant results. Shearing periodically occurs between the westward moving pack ice (3 to 10 km/d) within the Pacific Gyre and the fast ice along the coast, forming major grounded shear and pressure ridges between the 10 to 40 m isobaths. Ridges occur in patterns conforming to known shoals. The zone of grounded ridges, called stamukhi zone, protects the inner shelf and coast from marine energy and pack ice forces. Relatively undeformed fast ice grows inshore of the stamukhi zone. The boundary is explained in terms of pack ice drift and major promontories and shoals. Intense ice gaging, highly disrupted sediments, and landward migration of shoals suggest that much of the available marine energy is expended on the sea floor within the stamukhi zone. Naleds (products of river icings) on the North Slope are more abundant east than west of the Colville River. Their location, growth, and decay were studied from LANDSAT imagery.

  17. Seasonal variability of water mass distribution in the southeastern Beaufort Sea determined by total alkalinity and delta O-18

    OpenAIRE

    Lansard, B; Mucci, A.; L.A. Miller; Macdonald, R.W.; Gratton, Y

    2012-01-01

    ISI Document Delivery No.: 903QF Times Cited: 10 Cited Reference Count: 120 Cited References: AAGAARD K, 1981, DEEP-SEA RES, V28, P529, DOI 10.1016/0198-0149(81)90115-1 Alkire MB, 2006, J GEOPHYS RES-OCEANS, V111, DOI 10.1029/2005JC003446 ANDERSON LG, 1990, J GEOPHYS RES-OCEANS, V95, P1703, DOI 10.1029/JC095iC02p01703 Anderson LG, 2001, POLAR RES, V20, P225, DOI 10.1111/j.1751-8369.2001.tb00060.x Anderson LG, 2004, J GEOPHYS RES-OCEANS, V109, DOI [10.1029/2003JC002120, 10.1029/2003JC001773] [...

  18. Carbon sources in suspended particles and surface sediments from the Beaufort Sea revealed by molecular lipid biomarkers and compound-specific isotope analysis

    Directory of Open Access Journals (Sweden)

    I. Tolosa

    2013-03-01

    Full Text Available Molecular lipid biomarkers (hydrocarbons, alcohols, sterols and fatty acids and compound-specific isotope analysis of suspended particulate organic matter (SPM and surface sediments of the Mackenzie Shelf and slope (southeast Beaufort Sea, Arctic Ocean were studied in summer 2009. The concentrations of the molecular lipid markers, characteristic of known organic matter sources, were grouped and used as proxies to evaluate the relative importance of fresh algal, detrital algal, fossil, C3 terrestrial plants, bacterial and zooplankton material in the organic matter (OM of this area. Fossil and detrital algal contributions were the major fractions of the freshwater SPM from the Mackenzie River with ~34% each of the total molecular biomarkers. Fresh algal, C3 terrestrial, bacterial and zooplanktonic components represented much lower percentages, 17, 10, 4 and 80%, with a minor contribution of fossil and C3 terrestrial biomarkers. Characterization of the sediments revealed a major sink of refractory algal material mixed with some fresh algal material, fossil hydrocarbons and a small input of C3 terrestrial sources. In particular, the sediments from the shelf and at the mouth of the Amundsen Gulf presented the highest contribution of detrital algal material (60–75%, whereas those from the slope contained the highest proportion of fossil (40% and C3 terrestrial plant material (10%. Overall, considering that the detrital algal material is marine derived, autochthonous sources contributed more than allochthonous sources to the OM lipid pool. Using the ratio of an allochthonous biomarker (normalized to total organic carbon, TOC found in the sediments to those measured at the river mouth water, we estimated that the fraction of terrestrial material preserved in the sediments accounted for 30–40% of the total carbon in the inner shelf sediments, 17% in the outer shelf and Amundsen Gulf and up to 25% in the slope sediments. These estimates are low

  19. Ecosystem function and particle flux dynamics across the Mackenzie Shelf (Beaufort Sea, Arctic Ocean: an integrative analysis of spatial variability and biophysical forcings

    Directory of Open Access Journals (Sweden)

    A. Forest

    2012-08-01

    low fractal dimension of settling particles (1.26 and the high contribution (~94 % of fast-sinking small aggregates (<1 mm; 20–30 m d−1 to the mass fluxes suggested that settling material across the region was overall fluffy, porous, and likely resulting from the aggregation of marine detritus, gel-like substances and ballast minerals. Our study demonstrates that vertical POC fluxes in Arctic shelf systems are spatially complex, sensitive to environmental forcings, and determined by both physicochemical mechanisms and food web functioning. In conclusion, we hypothesize that the incorporation of terrestrial matter into the Beaufort Sea food web could be catalyzed by bacteria via the incorporation of dissolved terrestrial carbon liberated through the photo-cleavage and/or hydrolysis of land-derived POC interweaved with marine aggregates.

  20. Size distribution of particles and zooplankton across the shelf-basin system in Southeast Beaufort Sea: combined results from an Underwater Vision Profiler and vertical net tows

    Directory of Open Access Journals (Sweden)

    A. Forest

    2011-11-01

    Full Text Available The size distribution and mean spatial trends of large particles (>100 μm, in equivalent spherical diameter, ESD and mesozooplankton were investigated across the Mackenzie Shelf (Southeast Beaufort Sea, Arctic Ocean in July–August 2009. Our main objective was to combine results from an Underwater Vision Profiler 5 (UVP5 and traditional net tows (200 μm mesh size to characterize the structural diversity and functioning of the Arctic shelf-basin ecosystem and to assess the large-scale correspondence between the two methodological approaches. The core dataset comprised 154 UVP5 profiles and 29 net tows conducted in the shelf (<100 m isobath, slope (100–1000 m and basin (>1000 m regions of the study area. The mean abundance of total particles and zooplankton in the upper water column (<75 m depth declined exponentially with increasing distance from shore. Vertical and latitudinal patterns in total particle concentration followed those of chlorophyll-a (chl-a concentration, with maximum values between 30 and 70 m depth. Based on the size-spectra derived from the UVP5 dataset, living organisms (0.1–10 mm ESD accounted for an increasingly large proportion of total particle abundance (from 0.1% to > 50 % when progressing offshore and as the ESD of particles was increasing. Both the UVP5 and net tows determined that copepods dominated the zooplankton community (~78–94 % by numbers and that appendicularians were generally the second most abundant group (~1–11 %. The vertical distribution patterns of copepods and appendicularians indicated a close association between primary production and the main grazers. Manual taxonomic counts and ZooScan image analyses shed further light on the size-structure and composition of the copepod community – which was dominated at ~95 % by a guild of 10 typical taxa. The size distributions of copepods, as evaluated with the 3 methods (manual counts, ZooScan and UVP5, showed consistent patterns co

  1. Size distribution of particles and zooplankton across the shelf-basin system in southeast Beaufort Sea: combined results from an Underwater Vision Profiler and vertical net tows

    Directory of Open Access Journals (Sweden)

    A. Forest

    2012-04-01

    Full Text Available The size distribution and mean spatial trends of large particles (>100 μm, in equivalent spherical diameter, ESD and mesozooplankton were investigated across the Mackenzie Shelf (southeast Beaufort Sea, Arctic Ocean in July–August 2009. Our main objective was to combine results from an Underwater Vision Profiler 5 (UVP5 and traditional net tows (200 μm mesh size to characterize the structural diversity and functioning of the Arctic shelf-basin ecosystem and to assess the large-scale correspondence between the two methodological approaches. The core dataset comprised 154 UVP5 profiles and 29 net tows conducted in the shelf (<100 m isobath, slope (100–1000 m and basin (>1000 m regions of the study area. The mean abundance of total particles and zooplankton in the upper water column (<75 m depth declined exponentially with increasing distance from shore. Vertical and latitudinal patterns in total particle concentration followed those of chlorophyll a (chl a concentration, with maximum values between 30 and 70 m depth. Based on the size-spectra derived from the UVP5 dataset, living organisms (0.1–10 mm ESD accounted for an increasingly large proportion of total particle abundance (from 0.1 % to >50 % when progressing offshore and as the ESD of particles was increasing. Both the UVP5 and net tows determined that copepods dominated the zooplankton community (~78–94 % by numbers and that appendicularians were generally the second most abundant group (~1–11 %. The vertical distribution patterns of copepods and appendicularians indicated a close association between primary production and the main grazers. Manual taxonomic counts and ZooScan image analyses shed further light on the size-structure and composition of the copepod community – which was dominated at ~95 % by a guild of 10 typical taxa. The size distributions of copepods, as evaluated with the 3 methods (manual counts, ZooScan and UVP5, showed consistent patterns co

  2. Apparent optical properties of the Canadian Beaufort Sea – Part 2: The 1% and 1 cm perspective in deriving and validating AOP data products

    Directory of Open Access Journals (Sweden)

    S. B. Hooker

    2013-07-01

    Full Text Available A next-generation in-water profiler designed to measure the apparent optical properties (AOPs of seawater was developed and validated across a wide dynamic range of in-water properties. The new free-falling instrument, the Compact-Optical Profiling System (C-OPS, was based on sensors built with a cluster of 19 state-of-the-art microradiometers spanning 320–780 nm and a novel kite-shaped backplane. The new backplane includes tunable ballast, a hydrobaric buoyancy chamber, plus pitch and roll adjustments, to provide unprecedented stability and vertical resolution in near-surface waters. A unique data set was collected as part of the development activity plus the first major field campaign that used the new instrument, the Malina expedition to the Beaufort Sea in the vicinity of the Mackenzie River outflow. The data were of sufficient resolution and quality to show that errors – more correctly, uncertainties – in the execution of data sampling protocols were measurable at the 1% and 1 cm level with C-OPS. A theoretical sensitivity analysis as a function of three water types established by the peak in the remote sensing reflectance spectrum, Rrs(λ, revealed which water types and which parts of the spectrum were the most sensitive to data acquisition uncertainties. Shallow riverine waters were the most sensitive water type, and the ultraviolet and near-infrared spectral end members, which are critical to next-generation satellite missions, were the most sensitive parts of the spectrum. The sensitivity analysis also showed how the use of data products based on band ratios significantly mitigated the influence of data acquisition uncertainties. The unprecedented vertical resolution provided high-quality data products, which supported an alternative classification capability based on the spectral diffuse attenuation coefficient, Kd(λ. The Kd(320 and Kd(780 data showed how complex coastal systems can be distinguished two-dimensionally and how

  3. Estimating absorption coefficients of colored dissolved organic matter (CDOM using a semi-analytical algorithm for Southern Beaufort Sea (Canadian Arctic waters: application to deriving concentrations of dissolved organic carbon from space

    Directory of Open Access Journals (Sweden)

    A. Matsuoka

    2012-10-01

    Full Text Available A series of papers have suggested that freshwater discharge, including a large amount of dissolved organic matter (DOM, has increased since the middle of the 20th century. In this study, a semi-analytical algorithm for estimating light absorption coefficients of the colored fraction of DOM (CDOM was developed for Southern Beaufort Sea waters using remote sensing reflectance at six wavelengths in the visible spectral domain corresponding to MODIS ocean color sensor. This algorithm allows to separate colored detrital matter (CDM into CDOM and non-algal particles (NAP by determining NAP absorption using an empirical relationship between NAP absorption and particle backscattering coefficients. Evaluation using independent datasets, that were not used for developing the algorithm, showed that CDOM absorption can be estimated accurately to within an uncertainty of 35% and 50% for oceanic and turbid waters, respectively. In situ measurements showed that dissolved organic carbon (DOC concentrations were tightly correlated with CDOM absorption (r2 = 0.97. By combining the CDOM absorption algorithm together with the DOC versus CDOM relationship, it is now possible to estimate DOC concentrations in the near-surface layer of the Southern Beaufort Sea using satellite ocean color data. DOC concentrations in the surface waters were estimated using MODIS ocean color data, and the estimates showed reasonable values compared to in situ measurements. We propose a routine and near real-time method for deriving DOC concentrations from space, which may open the way to an estimate of DOC budgets for Arctic coastal waters.

  4. Estimating absorption coefficients of colored dissolved organic matter (CDOM using a semi-analytical algorithm for southern Beaufort Sea waters: application to deriving concentrations of dissolved organic carbon from space

    Directory of Open Access Journals (Sweden)

    A. Matsuoka

    2013-02-01

    Full Text Available A series of papers have suggested that freshwater discharge, including a large amount of dissolved organic matter (DOM, has increased since the middle of the 20th century. In this study, a semi-analytical algorithm for estimating light absorption coefficients of the colored fraction of DOM (CDOM was developed for southern Beaufort Sea waters using remote sensing reflectance at six wavelengths in the visible spectral domain corresponding to MODIS ocean color sensor. This algorithm allows the separation of colored detrital matter (CDM into CDOM and non-algal particles (NAP through the determination of NAP absorption using an empirical relationship between NAP absorption and particle backscattering coefficients. Evaluation using independent datasets, which were not used for developing the algorithm, showed that CDOM absorption can be estimated accurately to within an uncertainty of 35% and 50% for oceanic and coastal waters, respectively. A previous paper (Matsuoka et al., 2012 showed that dissolved organic carbon (DOC concentrations were tightly correlated with CDOM absorption in our study area (r2 = 0.97. By combining the CDOM absorption algorithm together with the DOC versus CDOM relationship, it is now possible to estimate DOC concentrations in the near-surface layer of the southern Beaufort Sea using satellite ocean color data. DOC concentrations in the surface waters were estimated using MODIS ocean color data, and the estimates showed reasonable values compared to in situ measurements. We propose a routine and near real-time method for deriving DOC concentrations from space, which may open the way to an estimate of DOC budgets for Arctic coastal waters.

  5. A 50% increase in the amount of terrestrial particles delivered by the Mackenzie River into the Beaufort Sea (Canadian Arctic Ocean) over the last 10 years

    OpenAIRE

    Doxaran, D; Devred, E.; M. Babin

    2015-01-01

    Global warming has a significant impact at the regional scale on the Arctic Ocean and surrounding coastal zones (i.e., Alaska, Canada, Greenland, Norway and Russia). The recent increase in air temperature has resulted in increased precipitations along the drainage basins of Arctic Rivers. It has also directly impacted land and seawater temperatures with the consequence of melting the permafrost and sea-ice. An increase in freshwater discharge by main Arctic rivers has ...

  6. Formation and ridging of flaw leads in the eastern Canadian Beaufort Sea. Special Session C06 on: “Physical, biological and biogeochemical processes associated with young thin ice types”

    Science.gov (United States)

    Prinsenberg, S. J.

    2009-12-01

    Formation and ridging of flaw leads in the eastern Canadian Beaufort Sea. Simon Prinsenberg1 and Yves Graton2 1Bedford Inst. of Oceanography, Fisheries and Oceans Canada P.O. Box1006, Dartmouth, Nova Scotia, B2Y 4A2, Canada prinsenbergs@mar.dfo-mpo.gc.ca 2Inst. National de la Recherche Scientifique-Eau, INRS-ETE University of Quebec at Quebec City, Quebec yvesgratton@eteinrs.ca During the winter of 2008, the flaw lead south of Banks Island repeatedly opened and closed representing an elongated region where periodically the large ice growth stimulates the densification of the surface layer due to salt rejection and instigates a local circulation pattern that will affect the biological processes of the region. Helicopter-borne sensors were available to monitor the aftermath of one of the rapid closing of the flaw lead into extensive elongated rubble field using a Canadian Ice breaker, CCGS Amundsen, as a logistic base. After the wind reversed a new open flaw lead 20km wide restarting a new flaw lead formation cycle. Ice thickness and surface roughness data were collected from the rubble field and adjacent open flaw lead with an Electromagnetic-Laser system. The strong wind event of April 4-5 2009 generated a large linear 1.5km wide ice rubble field up to 8-10m thick when the 60cm thick, 18km wide flaw lead was crunched into land-fast by the 1.5m thick offshore pack ice. It is expected that during rapid ice growth in a flaw lead, salt rejection increase the density of the surface water layer producing a surface depression (Low) and cyclonic circulation. In contrast at depth, the extra surface dense water produces a high in the horizontal pressure field and anti-cyclonic circulation which remains after the rapid ice growth within the flaw lead stops. One of such remnants may have been observed during the CFL-IPY winter survey.

  7. Morbillivirus and Toxoplasma exposure and association with hematological parameters for southern Beaufort Sea polar bears: potential response to infectious agents in a sentinel species

    Science.gov (United States)

    Kirk, Cassandra M.; Amstrup, Steven C.; Swor, Rhonda; Holcomb, Darce; O'Hara, Todd M.

    2010-01-01

    Arctic temperatures are increasing in response to greenhouse gas forcing and polar bears have already responded to changing conditions. Declines in body stature and vital rates have been linked to warming-induced loss of sea-ice. As food webs change and human activities respond to a milder Arctic, exposure of polar bears and other arctic marine organisms to infectious agents may increase. Because of the polar bear’s status as arctic ecosystem sentinel, polar bear health could provide an index of changing pathogen occurrence throughout the Arctic, however, exposure and monitoring protocols have yet to be established. We examine prevalence of antibodies to Toxoplasma gondii, and four morbilliviruses (canine distemper [CDV], phocine distemper [PDV], dolphin morbillivirus [DMV], porpoise morbillivirus [PMV]) including risk factors for exposure. We also examine the relationships between antibody levels and hematologic values established in the previous companion article. Antibodies to Toxoplasma gondii and morbilliviruses were found in both sample years. We found a significant inverse relationship between CDV titer and total leukocytes, neutrophils, monocytes, and eosinophils, and a significant positive relationship between eosinophils and Toxoplasma gondii antibodies. Morbilliviral prevalence varied significantly among age cohorts, with 1–2 year olds least likely to be seropositive and bears aged 5–7 most likely. Data suggest that the presence of CDV and Toxoplasma gondii antibodies is associated with polar bear hematologic values. We conclude that exposure to CDV-like antigen is not randomly distributed among age classes and suggest that differing behaviors among life history stages may drive probability of specific antibody presence.

  8. Beaufort Gyre hydrographic data: Temperature, salinity and transmissivity data from the Louis S St. Laurent in the Arctic Ocean, 2003 - 2008 (NODC Accession 0058268)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The major goal of the observational program is to determine the variability of different components of the Beaufort Gyre fresh water (ocean and sea ice) system and...

  9. Marine mammal observations collected using aircraft by ConocoPhillips in the Chukchi Sea, 1989-1991 and submitted as part of the ConocoPhillips and Shell Joint Monitoring Program in the Chukchi and Beaufort Seas (NODC Accession 0120533)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vessel- and aircraft-based marine mammal surveys in the Chukchi Sea collected from 1989 to 1991. The aerial marine mammal surveys were...

  10. Temperature, salinity and other variables collected from discrete sample and profile observations using CTD, PAR Sensor and other instruments from the NATHANIEL B. PALMER in the Arctic Ocean, Beaufort Sea and Bering Sea from 2003-07-05 to 2003-08-20 (NODC Accession 0116064)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0116064 includes biological, chemical, discrete sample, physical and profile data collected from NATHANIEL B. PALMER in the Arctic Ocean, Beaufort...

  11. AFSC/REFM: Beaufort Sea Marine Fish Survey, Beaufort Sea, Alaska, August 2008, Fisheries Interaction Team

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Alaska Fisheries Science Center's Status of Stocks and Multispecies Assessment (SSMA) Programs Fishery Interaction Team (FIT) conducted a fish survey in the...

  12. Marine mammal observations collected by aircraft and ship and submitted as part of the ConocoPhillips and Shell Joint Monitoring Program in the Chukchi and Beaufort Seas, 2006-2007 (NODC Accession 0120531)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set was collected as part of the Joint Monitoring Program during seismic activities in the Chukchi Sea. The 2006 data was collected by ship and aircraft...

  13. Annual Freshwater and Heat Content From 2003-2004: First Results from the Beaufort Gyre Observing System

    Science.gov (United States)

    Proshutinsky, A.; Krishfield, R.; Carmack, E.; McLaughlin, F.; Zimmerman, S.; Shimada, K.; Itoh, M.

    2004-12-01

    Seasonal variability of freshwater and heat content in the Beaufort Gyre will be presented, and causes of interannual changes will be discussed based on data from the Beaufort Gyre Freshwater Experiment (BGFE; http://www.whoi.edu/beaufortgyre), a prototype Ice-Tethered Profiler (ITP), and using CTD and XCTD data collected between 2001 and 2004. As part of the BGFE and in combination with the JWACS cruises on the CCGS Louis S. St. Laurent, three bottom-tethered moorings were deployed in August 2003 at coordinates 75N and 150W, 78N and 150W and 77N and 140W, and were recovered in August 2004. Year-long time series of sea ice draft (from upward looking sonars mounted at the top mooring float), temperature, salinity, and currents in the 50-2000m layer (from moored profilers), and bottom pressure (from pressure tide gauges) were retrieved from the instruments. Information in the upper ocean above 50 m, were also obtained from four drifting ice beacons which were also installed during the 2003 cruise and have telemetered temperature and salinity data at 10, 25, and 40 m for more than a full year. In order to continue collecting data from the Beaufort Gyre to study multiannual variability, the moorings were refurbished and redeployed in 2004 at the same locations and the buoy array was augmented with an ITP (providing CTD data with 1 meter vertical resolution and 6 hours temporal resolution down to 750 m) establishing the Beaufort Gyre Observing System (BGOS).

  14. A field survey of bird use at Beaufort Lagoon

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Bird surveys conducted at Beaufort Lagoon located along the northern periphery of the Arctic National Wildlife Refuge from June-September 1970. The Lagoon area...

  15. Crustal-scale geological and thermal models of the Beaufort-Mackenzie Basin, Arctic Canada

    Science.gov (United States)

    Sippel, Judith; Scheck-Wenderoth, Magdalena; Kröger, Karsten; Lewerenz, Björn

    2010-05-01

    of Tertiary deltaic sequences, AAPG Bulletin, 92(2): 225-247. Kroeger, K.F., di Primio, R. and Horsfield, B., (2009). Hydrocarbon flow modeling in complex structures (Mackenzie Basin, Canada), AAPG Bulletin, 93(9): 1-25. O'Leary, D.M., Ellis, R.M., Stephenson, R.A., Lane, L.S. and Zelt, C.A., 1995. Crustal structure of the northern Yukon and Mackenzie Delta, northwestern Canada, Journal of Geophysical Research 100(B7): 9905-9920. Stephenson, R.A., Coflin, K.C., Lane, L.S. and Dietrich, J.R., 1994. Crustal structure and tectonics of the southeastern Beaufort Sea continental margin, Tectonics, 13(2): 389-400.

  16. Beaufort Region Environmental Assessment and Monitoring program (BREAM). Final report for 1992/1993

    International Nuclear Information System (INIS)

    The Beaufort Region Environmental Assessment and Monitoring (BREAM) program was established to identify environmental research and monitoring priorities related to future hydrocarbon development activities in the Beaufort Sea and Mackenzie Delta region. The activities occurring during the third year of BREAM focused on major oil spills. Three planning meetings were held: a Project Initiation Meeting and technical meetings of the Community-Based Concerns and Catastrophic Oil Spill Working Groups. The initiation meeting had goals that included identifying specific tasks to be completed by the two Working Groups, discussion of contents and scope of materials being prepared for an oil spill workshop, and determining project schedules. The Community-Based Concerns group focused its work on identifying ecological concerns related to oil spills and their cleanup, identifying community-based ecological issues and concerns, and incorporating local and traditional knowledge into the BREAM program. The group suggested changes to the wording of existing impact hypotheses and oil spill scenarios, and recommended changes in a list of valued ecosystem components. The oil spill group reviewed ecological concerns related to oil spills, and reviewed each oil spill scenario and impact hypothesis selected for an interdisciplinary workshop held in February 1993. The workshop evaluated four of the most important oil spill impact hypotheses (offshore platform blowout, river barge spill of diesel fuel, under-ice spill from a pipeline river crossing, and a pipeline spill affecting mammals). Further research and monitoring related to a number of impact hypotheses was recommended by workshop participants. 57 refs., 29 figs., 12 tabs

  17. Pore pressure patterns in Tertiary succession and hydrodynamic implications, Beaufort-Mackenzie Basin, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Z.; Issler, D.R.; Osadetz, K.G.; Grasby, S.E. [Natural Resources Canada, Calgary, AB (Canada). Geological Survey of Canada

    2010-03-15

    The fluid pressure regime of the Beaufort-Mackenzie Basin was investigated using mud weight and pore pressure data from 250 exploration wells. Each of the four recognized patterns of pore pressure variation with depth are associated with a specific tectono-stratigraphic domain and indicate the relationship between compaction and tectonics, or other geological factors causing or redistributing the overpressure. In the southwest Beaufort Sea, overpressure likely results from compaction combined with northeast-southwest contractional tectonics. In the north, shale diapirism may produce fracture systems on top of anticlines, causing overpressured fluid to migrate to a shallower depth. Listric faulting prevails in the centre of the Mackenzie Delta, and compaction is the main controlling factor, while lithology and rate of deposition determine the depth of overpressure. Overpressure is mainly confined to Tertiary sedimentary successions, but it may be found in pre-Tertiary strata along the southeast basin margin, possibly in association with Cretaceous gas-generating source rocks. The spatial variation of pore pressure indicates that the upward expulsion of overpressured fluids is the primary driver of basin-scale flow. The pore pressure patterns suggest that regional fault zones can be both a barrier and a preferred flow path network to deep fluid fluxes. Fault zones tend to be regional barrier to lateral flow in an aquifer, but they represent the preferred flow arrangement for episodic vertical fluid migration. 47 ref., 8 figs.

  18. AIDJEX Beaufort Sea Upward Looking Sonar April 1976

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data contains Upward Looking Sonar (ULS) profiles of the underside of the Arctic pack ice along three transects whose total length is 777 nautical miles. The...

  19. Coastal Bathymetry of the Bering, Chuckhi, and Beaufort Seas

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Bathymetric contours were generated from soundings collected by National Ocean Service vessels from ~1900 to ~1971. The 1:250,000 maps are available for U.S....

  20. Ecological characteristics of core-use areas used by Bering-Chukchi-Beaufort (BCB) bowhead whales, 2006-2012

    Science.gov (United States)

    Citta, John J.; Quakenbush, Lori T.; Okkonen, Stephen R.; Druckenmiller, Matthew L.; Maslowski, Wieslaw; Clement-Kinney, Jaclyn; George, John C.; Brower, Harry; Small, Robert J.; Ashjian, Carin J.; Harwood, Lois A.; Heide-Jørgensen, Mads Peter

    2015-08-01

    The Bering-Chukchi-Beaufort (BCB) population of bowhead whales (Balaena mysticetus) ranges across the seasonally ice-covered waters of the Bering, Chukchi, and Beaufort seas. We used locations from 54 bowhead whales, obtained by satellite telemetry between 2006 and 2012, to define areas of concentrated use, termed "core-use areas". We identified six primary core-use areas and describe the timing of use and physical characteristics (oceanography, sea ice, and winds) associated with these areas. In spring, most whales migrated from wintering grounds in the Bering Sea to the Cape Bathurst polynya, Canada (Area 1), and spent the most time in the vicinity of the halocline at depths whales generally left in July, when copepods are expected to descend to deeper depths. Between 12 July and 25 September, most tagged whales were located in shallow shelf waters adjacent to the Tuktoyaktuk Peninsula, Canada (Area 2), where wind-driven upwelling promotes the concentration of calanoid copepods. Between 22 August and 2 November, whales also congregated near Point Barrow, Alaska (Area 3), where east winds promote upwelling that moves zooplankton onto the Beaufort shelf, and subsequent relaxation of these winds promoted zooplankton aggregations. Between 27 October and 8 January, whales congregated along the northern shore of Chukotka, Russia (Area 4), where zooplankton likely concentrated along a coastal front between the southeastward-flowing Siberian Coastal Current and northward-flowing Bering Sea waters. The two remaining core-use areas occurred in the Bering Sea: Anadyr Strait (Area 5), where peak use occurred between 29 November and 20 April, and the Gulf of Anadyr (Area 6), where peak use occurred between 4 December and 1 April; both areas exhibited highly fractured sea ice. Whales near the Gulf of Anadyr spent almost half of their time at depths between 75 and 100 m, usually near the seafloor, where a subsurface front between cold Anadyr Water and warmer Bering Shelf Water

  1. New sedimentological evidence supporting a catastrophic meltwater discharge event along the Beaufort margin, Arctic Ocean

    Science.gov (United States)

    Klotsko, S.; Driscoll, N. W.; Keigwin, L. D.; Mendenhall, B.

    2015-12-01

    In 2013, a cruise on the USCGC Healy mapped the Beaufort margin from Barrow, AK into the Amundsen Gulf using a towed CHIRP subbottom profiler and a hull-mounted Knudsen CHIRP subbottom profiler to study the deglaciation of the margin. Sediment cores were also acquired. New grain size analyses for three sediment cores will be presented. These records help constrain the flooding events captured in the existing grain size data from JPC 15, just east of the Mackenzie trough. This core shows evidence of multiple ice rafted debris events that were likely sourced from the retreat of the Amundsen ice stream. These layers have peaks in grain size around ~20 microns compared to the ~5 micron average for the rest of the core. The grain size peaks correlate to the high amplitude reflectors observed in the seismic CHIRP data. Similar reflectors are observed in the seismic data from two of the new core locations, one in the Mackenzie trough and one east of the trough. The seismic data from these stations also record a thick sediment package that is ~7 meters thick at its depocenter. This layer is interpreted to record a massive meltwater discharge event that entered the Arctic via the Mackenzie River. Oxygen isotope data from JPC 15 support an event at this location based on the covarying benthic and planktonic records. In our conceptual model, the pulses of freshwater from the Amundsen Gulf likely freshened the margin sufficiently that the major discharge event was then able to push the system over the edge. This catastrophic glacial lake draining out the Mackenzie River into the Beaufort Sea and export out of the Arctic into the North Atlantic caused diminished meridional overturning circulation - slowing of the conveyor belt thermohaline circulation - which, in turn, potentially caused the Younger Dryas cold period.

  2. Aspects of uranium mineralization in the Beaufort West Karoo

    International Nuclear Information System (INIS)

    The distribution and controlling factors of uranium mineralization in the sedimentary rocks of the Lower Beaufort Group have been investigated in the Beaufort West area between 220O' and 240O'E longitude and 320O' and 32045'S latitude. The mineralization is classified as 'primary' or 'secondary', depending on the time of emplacement and not on the oxidation state of the uranium minerals present. Petrographic and geochemical aspects of primary uranium deposition point to a syngenetic origin. Reconstruction of the paleodepossitional environment suggests that the primary mineralization is restricted to paleo-pools or -meander cut-offs where stagnant reducing conditions existed. From geological mapping done to the south of Beaufort West it appears that this uranium mineralization is located in an 'intermediate' paleo-depositional zone between the true fluvial and delta front environments. The indications of secondary uranium distribution and epigenetic concentration in 'rolls' within the area were studied along with various other aspects of such mineralization. The permeability of the arenaceous rocks in the area seems to be too low to host large uranium deposits of this kind. Detail geochemical soil sampling suggests that Zn, P, Co and As could be used as pathfinder elements for uranium. Although regional anomalies were investigated no meaningful pattern could be developed

  3. Behavior of bowhead whales of the Davis Strait and Bering/Beaufort stocks versus regional differences in human activities. Final report on Phase 2

    International Nuclear Information System (INIS)

    The objectives were to determine (1) whether there are differences in behavior between the Bering/Chukchi/Beaufort and the Davis Strait/Baffin Bay populations and (2), if so, whether the differences might be attributable to the long-term cumulative effects of exposure to the presumed greater amount of human activity in the former area. Phase 1 showed that there are some differences in behavior. The Phase 2 report documents the relative amounts of human activity in the two areas in 1974-86, and evaluates whether regional differences in whale behavior and in human activities may be related. Activities considered include bowhead hunting and other subsistence activities, commercial fishing and shipping, marine seismic exploration, offshore oil exploration, and low-level aircraft flights. Bering/Beaufort bowheads were subjected to at least 3-5 times as much human activity in 1974-86. Most differences in behavior between the two stocks were better explained by environmental or biological factors than by disturbance. However, for bowheads migrating in autumn, regional differences in behavior may be related to the whaling that occurs in the Beaufort Sea in autumn

  4. Vertical Structure and Dynamics of the Beaufort Gyre Subsurface Layer from ADCP Obervations

    Science.gov (United States)

    Torres, D. J.; Krishfield, R. A.; Proshutinsky, A. Y.; Timmermans, M. L. E.

    2014-12-01

    As part of the Beaufort Gyre Observing System (BGOS), several Acoustic Doppler Current Profilers (ADCPs) have been maintained at moorings in different locations in the Canada Basin since 2005 to measure upper ocean velocities and sea ice motion. The ADCP data have been analyzed to better understand relationships among different components of forcing driving the sea ice and upper ocean layer including: winds, tides, and horizontal and vertical density gradients in the ocean. Specific attention is paid to data processing and analysis to separate inertial and tidal motions in these regions in the vicinity of the critical latitudes. In addition, we describe the dynamic characteristics of halocline eddies and estimate their kinetic energy and their role in the total energy balance in this region. Ice-Tethered Profiler (ITP) data are used in conjunction with the ADCP measurements to identify relationships between T-S and vertical velocity structures in the mixed layer and deeper. Seasonal and interannual variability in all parameters are also discussed and causes of observed changes are suggested.

  5. Natural Gas Hydrates in the Offshore Beaufort-Mackenzie Basin-Study of a Feasible Energy Source II

    International Nuclear Information System (INIS)

    In the offshore part of Beaufort-Mackenzie Basin depth of methane hydrate stability reaches more than 1.5 km. However, there are areas in the western part of the basin where there are no conditions of methane hydrate stability. Construction of the first contour maps displaying thickness of hydrate stability zones as well as hydrate stability zone thicknesses below permafrost in the offshore area, shows that these zones can reach 1200 m and 900 m, respectively. Depth to the base of ice-bearing relict permafrost under the sea (depth of the -1oC isotherm-ice-bearing permafrost base) and regional variations of geothermal gradient are the main controlling factors. Hydrostatic pressures in the upper 1500 m are the rule. History of methane hydrate stability zone is related mainly to the history of permafrost and it reached maximum depth in early Holocene. More recently, the permafrost and hydrate zone is diminishing because of sea transgression. Reevaluation of the location of possible gas hydrate occurrences is done from the analysis of well logs and other indicators in conjunction with knowledge of the hydrate stability zone. In the offshore Beaufort-Mackenzie Basin, methane hydrate occurs in 21 wells. Nine of these locations coincides with underlying conventional hydrocarbon occurrences. Previous analyses place some of the hydrate occurrences at greater depths than proposed for the methane hydrate-stability zone described in this study. Interpretation of geological cross sections and maps of geological sequences reveals that hydrates are occurring in the Iperk-Kugmallit sequence. Hydrate-gas contact zones, however, are possible in numerous situations. As there are no significant geological seals in the deeper part of the offshore basin (all hydrates are within Iperk), it is suggested that overlying permafrost and hydrate stability zone acted as the only trap for upward migrating gas during the last tens of thousand of years (i.e., Sangamonian to Holocene)

  6. MITAS-2009 Expedition, U.S. Beaufort Shelf and Slope—Lithostratigraphy Data Report

    Energy Technology Data Exchange (ETDEWEB)

    Rose, K.; Johnson, J.E.; Phillips, S.C.; Smith, J.; Reed, A.; Disenhof, C.; Presley, J.

    2012-09-17

    The volume of methane released through the Arctic Ocean to the atmosphere and its potential role in the global climate cycle have increasingly become the focus of studies seeking to understand the source and origin of this methane. In 2009, an international, multi-disciplinary science party aboard the U.S. Coast Guard icebreaker Polar Sea successfully completed a trans-U.S. Beaufort Shelf expedition aimed at understanding the sources and volumes of methane across this region. Following more than a year of preliminary cruise planning and a thorough site evaluation, the Methane in the Arctic Shelf/Slope (MITAS) expedition departed from the waters off the coast of Barrow, Alaska in September 2009. The expedition was organized with an international shipboard science team consisting of 33 scientists with the breadth of expertise necessary to meet the expedition goals. NETL researchers led the expedition’s initial core processing and lithostratigraphic evaluations, which are the focus of this report. This data report is focused on the lithostratigraphic datasets from the recovered vibra cores and piston cores. Operational information about the piston and vibra cores such as date acquired, core name, total length, water depth, and geographic location is provided. Once recovered, gas samples were immediately collected from cores. In addition, each core was run through the Geotek multi-sensor core logger for magnetic susceptibility, P-wave velocity, resistivity, and gamma-density measurements (Rose et al., 2010). After the samples and measurements were completed, the cores were split into working and archive halves. Visual core descriptions of the archive half was completed for each core. Samples for shipboard smear slides, coarse fractions, and XRD analyses were collected, as well as corresponding samples for post-cruise grain size analysis from the working half of each core. Line scan images of the split core surfaces were collected post-expedition. The methods used to

  7. Diversity, abundance and community structure of benthic macro- and megafauna on the Beaufort shelf and slope.

    Directory of Open Access Journals (Sweden)

    Jessica Nephin

    Full Text Available Diversity and community patterns of macro- and megafauna were compared on the Canadian Beaufort shelf and slope. Faunal sampling collected 247 taxa from 48 stations with box core and trawl gear over the summers of 2009-2011 between 50 and 1,000 m in depth. Of the 80 macrofaunal and 167 megafaunal taxa, 23% were uniques, present at only one station. Rare taxa were found to increase proportional to total taxa richness and differ between the shelf (< 100 m where they tended to be sparse and the slope where they were relatively abundant. The macrofauna principally comprised polychaetes with nephtyid polychaetes dominant on the shelf and maldanid polychaetes (up to 92% in relative abundance/station dominant on the slope. The megafauna principally comprised echinoderms with Ophiocten sp. (up to 90% in relative abundance/station dominant on the shelf and Ophiopleura sp. dominant on the slope. Macro- and megafauna had divergent patterns of abundance, taxa richness (α diversity and β diversity. A greater degree of macrofaunal than megafaunal variation in abundance, richness and β diversity was explained by confounding factors: location (east-west, sampling year and the timing of sampling with respect to sea-ice conditions. Change in megafaunal abundance, richness and β diversity was greatest across the depth gradient, with total abundance and richness elevated on the shelf compared to the slope. We conclude that megafaunal slope taxa were differentiated from shelf taxa, as faunal replacement not nestedness appears to be the main driver of megafaunal β diversity across the depth gradient.

  8. Comparing the theoretical versions of the Beaufort scale, the T-Scale and the Fujita scale

    Science.gov (United States)

    Meaden, G. Terence; Kochev, S.; Kolendowicz, L.; Kosa-Kiss, A.; Marcinoniene, Izolda; Sioutas, Michalis; Tooming, Heino; Tyrrell, John

    2007-02-01

    2005 is the bicentenary of the Beaufort Scale and its wind-speed codes: the marine version in 1805 and the land version later. In the 1920s when anemometers had come into general use, the Beaufort Scale was quantified by a formula based on experiment. In the early 1970s two tornado wind-speed scales were proposed: (1) an International T-Scale based on the Beaufort Scale; and (2) Fujita's damage scale developed for North America. The International Beaufort Scale and the T-Scale share a common root in having an integral theoretical relationship with an established scientific basis, whereas Fujita's Scale introduces criteria that make its intensities non-integral with Beaufort. Forces on the T-Scale, where T stands for Tornado force, span the range 0 to 10 which is highly useful world wide. The shorter range of Fujita's Scale (0 to 5) is acceptable for American use but less convenient elsewhere. To illustrate the simplicity of the decimal T-Scale, mean hurricane wind speed of Beaufort 12 is T2 on the T-Scale but F1.121 on the F-Scale; while a tornado wind speed of T9 (= B26) becomes F4.761. However, the three wind scales can be uni-fied by either making F-Scale numbers exactly half the magnitude of T-Scale numbers [i.e. F'half = T / 2 = (B / 4) - 4] or by doubling the numbers of this revised version to give integral equivalence with the T-Scale. The result is a decimal formula F'double = T = (B / 2) - 4 named the TF-Scale where TF stands for Tornado Force. This harmonious 10-digit scale has all the criteria needed for world-wide practical effectiveness.

  9. The influence of the Mackenzie River plume on distribution and diversity of marine larval fish assemblages on the Canadian Beaufort Shelf

    Science.gov (United States)

    Wong, Sally; Walkusz, Wojciech; Hanson, Mark; Papst, Michael H.

    2013-11-01

    In the Beaufort Sea, freshwater input from the Mackenzie River creates a relatively warm and turbid plume across the coastal shelf region. To determine the influence of this plume on marine larval fish abundance, distribution, and assemblages, we sampled larval fish during July and August of 2007 using 500 μm bongo nets on transects across the plume gradient at three sampling stations per transect, along with oceanographic measurements. Three larval fish assemblages were identified within three distinct oceanographic zones: intense plume, diffuse plume and oceanic. The intense plume assemblage was dominated by Saffron cod (Eleginus gracilis) and Pacific herring (Clupea pallasii); the diffuse plume assemblage was dominated by the Pricklebacks (sub-family Lumpeninae); and the oceanic assemblage was dominated by Arctic cod (Boreogadus saida). Even though there were differences in relative abundance of particular species among these areas, no significant differences in total abundances of larval fish were found.

  10. De Beaufort, een aanzienlijke familie tijdens de Republiek, de Bataafs-Franse tijd en het Koninkrijk 1613-1876

    OpenAIRE

    Melchers, R.R.J.

    2014-01-01

    In 1613 Pierre de Beaufort aged 18, left the French town of Sedan for the Dutch Republic. At his death in 1661 in Hulst he had become a man of distinction. More than 200 years later on 30 May 1868 his direct descendant Pieter de Beaufort received from the Hoge Raad van Adel (High Court of Nobility) a diploma signed by King Willem I in which he was raised to the peerage. This elevation indicates that Pieter de Beaufort belonged to the prominent families of the country. The patent of nobility r...

  11. Implementasi Three-Pass Protocol dengan Kombinasi Algoritma Beaufort Cipher dan One Time Pad untuk Pengamanan Data

    OpenAIRE

    Sujiono, Dina Meiladya Rizki

    2016-01-01

    Cryptography can be divided into two types: classical cryptography and modern cryptography. In general, modern cryptography is more trusted than classical cryptography because it has a great security. But implementation of combination two or more classical cryptography algorithm is also used by some people because of their easiness and good security. Beaufort Cipher and One Time Pad algorithm are categorized into classical cryptography. The security of Beaufort Cipher algorithm depends on the...

  12. Beaufort Sea oil spills state of knowledge review and identification of key issues

    International Nuclear Information System (INIS)

    From the 1960s to the 1980s, offshore petroleum exploration activities were carried out by several companies in the Canadian Arctic and important resources of oil and gas were discovered. These reserves have not been exploited until now, but exploration activities are expected to increase in the coming years due to changing market conditions and to result in greater risks of accidental spills. The aim of this report is to review existing knowledge of oil spills in Arctic waters, identify the associated issues and provide a reference document for the stakeholders. A literature review of the subject was carried out by the study team using online database search services, in-house libraries and Environment Canada's library. In addition, the study team held a workshop in October 2009 to present their findings and discuss key issues with stakeholders. This document provides the findings of the study team.

  13. AFSC/NMML: Distribution of cetaceans in the Bering, Chukchi, and Beaufort Seas, 2010-2014

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — As part of several inter-agency agreements between the National Marine Mammal Laboratory (NMML) and the Bureau of Ocean Energy Management (BOEM), ship-based visual...

  14. 77 FR 10707 - Safety Zone; NOBLE DISCOVERER, Outer Continental Shelf Drillship, Chukchi and Beaufort Seas, Alaska

    Science.gov (United States)

    2012-02-23

    ... Federal Register (73 FR 3316). Public Meeting The Coast Guard does not plan to hold a public meeting. But... of the vessel located at the coordinates listed in Table 1. These coordinates are based upon UTM...

  15. Final environmental impact statement, Beaufort Sea oil and gas development/Northstar Project. Appendix K (continued)

    International Nuclear Information System (INIS)

    BP Exploration (Alaska) Inc. (BPXA) submitted a permit application to the US Army Engineer District, Alaska to initiate the review process for BPXA's plans to develop and produce oil and gas from the Northstar Unit. This report contains Appendices K (continued) of an Environmental Impact Statement which was undertaken to identify and evaluate the potential effects the proposed project may have on the environment

  16. Rates of summertime biological productivity in the Beaufort Gyre: A comparison between the low and record-low ice conditions of August 2011 and 2012

    Science.gov (United States)

    Stanley, Rachel H. R.; Sandwith, Zoe O.; Williams, William J.

    2015-07-01

    The Arctic Ocean is changing rapidly as the global climate warms but it is not well known how these changes are affecting biological productivity and the carbon cycle. Here we study the Beaufort Gyre region of the Canada Basin in August and use the large reduction in summertime sea ice extent from 2011 to 2012 to investigate potential impacts of climate warming on biological productivity. We use the gas tracers O2/Ar and triple oxygen isotopes to quantify rates of net community production (NCP) and gross oxygen production (GOP) in the gyre. Comparison of the summer of 2011 with the summer of 2012, the latter of which had record low sea ice coverage, is relevant to how biological productivity might change in a seasonally ice-free Arctic Ocean. We find that, in the surface waters measured here, GOP in 2012 is significantly greater than in 2011, with the mean basin-wide 2012 GOP = 38 ± 3 mmol O2 m- 2 d- 1 whereas in 2011, mean basin GOP = 16 ± 5 mmol O2 m- 2 d- 1. We hypothesize that this is because the lack of sea ice and consequent increase in light penetration allows photosynthesis to increase in 2012. However, despite the increase in GOP, NCP is the same in the two years; mean NCP in 2012 is 3.0 ± 0.2 mmol O2 m- 2 y- 1 and in 2011 is 3.1 ± 0.2 mmol O2 m- 2 y- 1. This suggests that the heterotrophic community (zooplankton and/or bacteria) increased its activity as well and thus respired the additional carbon produced by the increased photosynthetic production. In both years, stations on the shelf had GOP 3 to 5 times and NCP 2 to 10 times larger than the basin stations. Additionally, we show that in 2011, the NCP/GOP ratio is smallest in regions with highest ice cover, suggesting that the microbial loop was more efficient at recycling carbon in regions where the ice was just starting to melt. These results highlight that although satellite chlorophyll records show, and many models predict, an increase in summertime primary production in the Arctic Basin as it

  17. Impact of river discharge, upwelling and vertical mixing on the nutrient loading and productivity of the Canadian Beaufort Shelf

    Directory of Open Access Journals (Sweden)

    J.-É. Tremblay

    2013-10-01

    Full Text Available The concentrations and elemental stoichiometry of particulate and dissolved pools of carbon (C, nitrogen (N, phosphorus (P and silicon (Si in the southeast Beaufort Sea during summer 2009 were assessed and compared with those of surface waters provided by the Mackenzie river as well as by winter mixing and upwelling of upper halocline waters at the shelf break. Neritic surface waters showed a clear enrichment in dissolved and particulate organic carbon (DOC and POC, respectively, nitrate, total particulate nitrogen (TPN and dissolved organic nitrogen (DON originating from the river. Silicate as well as bulk DON and DOC declined in a conservative manner away from the delta's outlet, whereas nitrate dropped non-conservatively to very low background concentrations inside the brackish zone. By contrast, the excess of soluble reactive P (SRP present in oceanic waters declined in a non-conservative manner toward the river outlet, where concentrations were very low and consistent with P shortage in the Mackenzie River. These opposite gradients imply that the admixture of Pacific-derived, SRP-rich water is necessary to allow phytoplankton to use river-derived nitrate and to a lesser extent DON. A coarse budget based on concurrent estimates of primary production shows that river N deliveries support a small fraction of primary production when considering the entire shelf, due to the ability of phytoplankton to thrive in the subsurface chlorophyll maximum beneath the thin, nitrate-depleted river plume. Away from shallow coastal bays, local elevations in the concentration of primary production and dissolved organic constituents were consistent with upwelling at the shelf break. By contrast with shallow winter mixing, nutrient deliveries by North American rivers and upwelling relax surface communities from N limitation and permit a more extant utilization of the excess SRP entering through Bering Strait. In this context, increased nitrogen supply by rivers

  18. Sea ice terminology

    Energy Technology Data Exchange (ETDEWEB)

    1980-09-01

    A group of definitions of terms related to sea ice is presented, as well as a graphic representation of late winter ice zonation of the Beaufort Sea Coast. Terms included in the definition list are belt, bergy bit, bight, brash ice, calving, close pack ice, compacting, compact pack ice, concentration, consolidated pack ice, crack, diffuse ice edge, fast ice, fast-ice boundary, fast-ice edge, first-year ice, flaw, flaw lead, floe, flooded ice, fractured, fractured zone, fracturing, glacier, grey ice, grey-white ice, growler, hummock, iceberg, iceberg tongue, ice blink, ice boundary, ice cake, ice edge, ice foot, ice free, ice island, ice shelf, large fracture, lead, medium fracture, multiyear ice, nilas, old ice, open pack ice, open water, pack ice, polar ice, polynya, puddle, rafted ice, rafting, ram, ridge, rotten ice, second-year ice, shearing, shore lead, shore polynya, small fracture, strip, tabular berg, thaw holes, very close pack ice, very open pack ice, water sky, young coastal ice, and young ice.

  19. Environment of deposition and stratigraphy of the uranium-bearing strata around Beaufort West, South Africa

    International Nuclear Information System (INIS)

    Palynological analyses of some 50 samples collected from uranium-bearing strata - as well as the layers immediately above and below them - around Beaufort West, South Africa, indicate that these sediments were laid down in a wide, rather shallow delta in Late Permian times. Most of the sediments are fluvio-deltaic, and most of the plant remains were transported from the north, the hinterland in those times. A considerable percentage of the microfossils, e.g. Veryhachium and hystrichospheres, are clearly from a marine environment. The occurrence of marine microfossils in the spectrum, as compared with those of terrestrial provenance, increases considerably southwards

  20. The influence of winter cloud on summer sea ice in the Arctic, 1983-2013

    Science.gov (United States)

    Letterly, Aaron; Key, Jeffrey; Liu, Yinghui

    2016-03-01

    Arctic sea ice extent has declined dramatically over the last two decades, with the fastest decrease and greatest variability in the Beaufort, Chukchi, and East Siberian Seas. Thinner ice in these areas is more susceptible to changes in cloud cover, heat and moisture advection, and surface winds. Using two climate reanalyses and satellite data, it is shown that increased wintertime surface cloud forcing contributed to the 2007 summer sea ice minimum. An analysis over the period 1983-2013 reveals that reanalysis cloud forcing anomalies in the East Siberian and Kara Seas precondition the ice pack and, as a result, explain 25% of the variance in late summer sea ice concentration. This finding was supported by Moderate Resolution Imaging Spectroradiometer cloud cover anomalies, which explain up to 45% of the variance in sea ice concentration. Results suggest that winter cloud forcing anomalies in this area have predictive capabilities for summer sea ice anomalies across much of the central and Eurasian Arctic.

  1. Fine-resolution simulation of surface current and sea ice in the Arctic Mediterranean Seas

    Institute of Scientific and Technical Information of China (English)

    LIU Xiying; ZHANG Xuehong; YU Rucong; LIU Hailong; LI Wei

    2007-01-01

    A fine-resolution model is developed for ocean circulation simulation in the National Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG),Chinese Academy of Sciences, and is applied to simulate surface current and sea ice variations in the Arctic Mediterranean Seas. A dynamic sea ice model in elastic-viscous-plastic rheology and a thermodynamic sea ice model are employed. A 200-year simulation is performed and a dimatological average of a 10-year period (141 st-150 th) is presented with focus on sea ice concentration and surface current variations in the Arctic Mediterranean Seas. The model is able to simulate well the East Greenland Current, Beaufort Gyre and the Transpolar Drift, but the simulated West Spitsbergen Current is small and weak. In the March climatology, the sea ice coverage can be simulated well except for a bit more ice in east of Spitsbergen Island. The result is also good for the September scenario except for less ice concentration east of Greenland and greater ice concentration near the ice margin. The extra ice east of Spitsbergen Island is caused by sea ice current convergence forced by atmospheric wind stress.

  2. Inferred gas hydrate and permafrost stability history models linked to climate change in the Beaufort-Mackenzie Basin, Arctic Canada

    Czech Academy of Sciences Publication Activity Database

    Majorowicz, J.; Šafanda, Jan; Osadetz, K.

    2012-01-01

    Roč. 8, č. 2 (2012), s. 667-682. ISSN 1814-9324 Institutional research plan: CEZ:AV0Z30120515 Institutional support: RVO:67985530 Keywords : climate change * Beaufort-Mackenzie Basin * permafrost Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 3.556, year: 2012

  3. [Cryptomonad alga Rhodomonas sp. (Cryptophyta, Pyrenomonadaceae) bloom in the redox zone of the basins separating from the White Sea].

    Science.gov (United States)

    Krasnova, E D; Pantyulin, A N; Matorin, D N; Todorenko, D A; Belevich, T A; Milyutina, I A; Voronov, D A

    2014-01-01

    Bloom of a cryptomonad alga Rhodomonas sp. (Cryptophyta, Pyrenomonadaceae) was observed in the chemocline of saline basins separating from the White Sea, resulting in red coloration of the relevant water layer. According to the sequence of the 18S nuclear rRNA gene, this species was identical to Rhodomonas sp.RCC2020 (GenBank accession no. JN934672) from the Beaufort Sea. The presence of the red layer formed by mass development of Rhodomonas sp. is considered as an indicator of a certain stage of separation of a basin from the sea. PMID:25844445

  4. Photogrammetry for the preparation of archaeological excavation. A 3D restitution according to modern and archive images of Beaufort Castle landscape (Lebanon)

    OpenAIRE

    Grussenmeyer, Pierre; Yasmine, J.

    2004-01-01

    This paper presents the contribution of photogrammetry within the framework of the documentation of the Beaufort castle (South Lebanon), also called Qalaat el-Chaqif (12-17th century). After the withdrawal of the Israeli army of southern Lebanon, the Lebanese government asked for a consulting firm (J. Yasmine, DGA consultant) to establish general tender documents for the restoration of the Beaufort castle. Many parts of the site were destroyed or buried because of the war. In 2002, the castle...

  5. Upper Permian magnetic stratigraphy of the lower Beaufort Group, Karoo Basin

    Science.gov (United States)

    Lanci, L.; Tohver, E.; Wilson, A.; Flint, S.

    2013-08-01

    We carried out a magnetostratigraphic and geochronological study of late Permian sediments in the Karoo Basin of the Western Cape Province, South Africa. A continuous, ~700 m thick section of deltaic sediments of the upper Waterford Formation (uppermost Ecca Group) and the fluvial sediments of the Abrahamskraal Formation (lowermost Beaufort Group) were sampled at the meter scale. U-Pb dating of zircons from interbedded volcanic ash beds by ion microprobe (SHRIMP) provided absolute age constraints on the age of the sedimentary rocks. Paleomagnetic analysis reveals a partial overprint of the Natural Remanent Magnetization (NRM) that is tentatively ascribed to the emplacement of the Karoo Large Igneous Province in the Western Cape region during the middle Jurassic. A stable component of the NRM was found at temperatures higher than 450 °C and was interpreted as a Characteristic Remanent Magnetization (ChRM) acquired during deposition, supported by a positive reversals test for this dual polarity ChRM. The virtual geomagnetic pole position for the Waterford and Abrahamskraal Formations computed from the average ChRM direction is in general agreement with the late Permian directions for stable Gondwana. A significantly different average inclination, and thus paleomagnetic pole position, is obtained by correcting the inclination shallowing error by the Elongation-Inclination method (Tauxe and Kent, 2004). The presence of both normal and reversed polarity zones indicate deposition after the end of the Kiaman Superchron, moreover the polarity sequence is in good agreement with the Illawarra sequence of Steiner (2006). Our results indicate a Capitanian (late Guadalupian) age for the Abrahamskraal Fm., in agreement with the Late Permian age, based on presence of Glossopteris flora and Dicynodont fauna, traditionally assigned to the fluvial-lacustrine sediments of the Beaufort Group. However, the U-Pb zircon ages of ca. 264-268 Ma suggest an age of 269 Ma for the top of the

  6. Recent Arctic Sea Level Variations from Satellites

    DEFF Research Database (Denmark)

    Andersen, Ole Baltazar; Piccioni, Gaia

    2016-01-01

    Sea level monitoring in the Arctic region has always been an extreme challenge for remote sensing, and in particular for satellite altimetry. Despite more than two decades of observations, altimetry is still limited in the inner Arctic Ocean. We have developed an updated version of the Danish...... Technical University's (DTU) Arctic Ocean altimetric sea level timeseries starting in 1993 and now extended up to 2015 with CryoSat-2 data. The time-series covers a total of 23 years, which allows higher accuracy in sea level trend determination. The record shows a sea level trend of 2.2 ± 1.1 mm/y for the...... region between 66°N and 82°N. In particular, a local increase of 15 mm/y is found in correspondence to the Beaufort Gyre. An early estimate of the mean sea level trend budget closure in the Arctic for the period 2005–2015 was derived by using the Equivalent Water Heights obtained from GRACE Tellus...

  7. Inferred gas hydrate and permafrost stability history models linked to climate change in the Beaufort-Mackenzie Basin, Arctic Canada

    Science.gov (United States)

    Majorowicz, J.; Safanda, J.; Osadetz, K.

    2012-03-01

    Atmospheric methane from episodic gas hydrate (GH) destabilization, the "clathrate gun" hypothesis, is proposed to affect past climates, possibly since the Phanerozoic began or earlier. In the terrestrial Beaufort-Mackenzie Basin (BMB), GHs occur commonly below thick ice-bearing permafrost (IBP), but they are rare within it. Two end-member GH models, where gas is either trapped conventionally (Case 1) or where it is trapped dynamically by GH formation (Case 2), were simulated using profile (1-D) models and a 14 Myr ground surface temperature (GST) history based on marine isotopic data, adjusted to the study setting, constrained by deep heat flow, sedimentary succession conductivity, and observed IBP and Type I GH contacts in Mallik wells. Models consider latent heat effects throughout the IBP and GH intervals. Case 1 GHs formed at ~0.9 km depth only ~1 Myr ago by in situ transformation of conventionally trapped natural gas. Case 2 GHs begin to form at ~290-300 m ~6 Myr ago in the absence of lithological migration barriers. During glacial intervals Case 2 GH layers expand both downward and upward as the permafrost grows downward through and intercalated with GHs. The distinctive model results suggest that most BMB GHs resemble Case 1 models, based on the observed distinct and separate occurrences of GHs and IBP and the lack of observed GH intercalations in IBP. Case 2 GHs formed >255 m, below a persistent ice-filled permafrost layer that is as effective a seal to upward methane migration as are Case 1 lithological seals. All models respond to GST variations, but in a delayed and muted manner such that GH layers continue to grow even as the GST begins to increase. The models show that the GH stability zone history is buffered strongly by IBP during the interglacials. Thick IBP and GHs could have persisted since ~1.0 Myr ago and ~4.0 Myr ago for Cases 1 and 2, respectively. Offshore BMB IBP and GHs formed terrestrially during Pleistocene sea level low stands. Where

  8. Degradation state of organic matter in surface sediments from the Beaufort Shelf: a lipid approach

    Science.gov (United States)

    Rontani, J.-F.; Charriere, B.; Petit, M.; Vaultier, F.; Heipieper, H. J.; Link, H.; Chaillou, G.; Sempéré, R.

    2012-03-01

    The lipid content of surface sediments collected on the Beaufort Shelf was examined. Particular attention was given to biotic and abiotic degradation products of sterols and monounsaturated fatty acids. By using sitosterol and campesterol degradation products as tracers of the degradation of terrestrial higher plant inputs and brassicasterol degradation products as tracers of degradation of phytoplanktonic organisms, it could be observed that autoxidation, photooxidation and biodegradation processes act much more intensively on higher plant debris than on phytoplanktonic organisms. Examination of oxidation products of monounsaturated fatty acids showed that photo- and autoxidation processes act more intensively on bacteria than on phytodetritus. Enhanced damages induced by singlet oxygen (transferred from senescent phytoplanktonic cells) in bacteria were attributed to the lack of an adapted antioxidant system in these microorganisms. The strong oxidative stress observed in the sampled sediments resulted in the production of significant amounts of epoxyacids and unusually very high proportions of monounsaturated fatty acids with a trans double bond. The formation of epoxyacids was attributed to peroxygenases (enzymes playing a protective role against the deleterious effects of fatty acid hydroperoxides in vivo), while cis/trans isomerization was probably induced by thiyl radicals produced during the reaction of thiols with hydroperoxides. Our results confirm the important role played by abiotic oxidative processes in the degradation of marine bacteria and do not support the generally expected refractory character of terrigenous material deposited in deltaic systems.

  9. Flume study on the concentration of ilmenite in fine-grained sand and implications concerning uranium mineralization in the Beaufort Group

    International Nuclear Information System (INIS)

    Uranium in the Beaufort Group may have been derived partly from the leaching of heavy minerals in the host sandstones. To establish the basic hydrodynamic controls on the distribution and concentration of heavy minerals under different flow regime conditions, three flume runs were conducted using natural sand similar to that of the Beaufort sandstones. Sinuous dunes showed the highest concentration of ilmenite, followed by linguoid ripples and upper flow regime plane beds. Relative bed roughness played a major role in determining the amount of heavy minerals left behind in the sediments. The results of the flume studies showed that trough cross-laminated sandstones may have the best potential for hosting uranium, which agrees with preliminary field observations in the Beaufort Group. 9 figs., 8 tabs., 20 refs

  10. Origin and fate of particulate organic matter in the southern Beaufort Sea - Amundsen Gulf region, Canadian Arctic

    DEFF Research Database (Denmark)

    Magen, Cedric; Chaillou, Gwenaelle; Crowe, Sean;

    2010-01-01

    diagenesis, and a refractory terrigenous component. A three-component mixing model explains the scatter observed in the stable isotope signatures of the sediment trap samples and accommodates an apparent two-component mixing model of the organic matter in sediments. The suspended matter in the water column...... contains organic matter varying from essentially labile and marine to mostly refractory and terrigenous. As it settles through the water column, the labile marine organic matter is degraded, and its original stable isotope signature changes towards the signature of the marine refractory component. This...

  11. AFSC/NMML: Bowhead Whale Feeding Ecology Study (BOWFEST): Aerial Survey in Chukchi and Beaufort Seas, 2007-2011

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Bowhead Whale Feeding Ecology Study (BOWFEST) was initiated in May 2007 through an Interagency Agreement between the Bureau of Ocean Energy Management (BOEM)...

  12. Final environmental impact statement, Beaufort Sea oil and gas development/Northstar Project. Appendices B through K

    International Nuclear Information System (INIS)

    BP Exploration (Alaska) Inc. (BPXA) submitted a permit application to the US. Army Engineer District, Alaska to initiate the review process for BPXA's plans to develop and produce oil and gas from the Northstar Unit. This report contains Appendices B--K of an Environmental Impact Statement which was undertaken to identify and evaluate the potential effects the proposed project may have on the environment

  13. Bowhead (Balaena mysticetus) and beluga (Delphinapterus leucas) whales in the Bering, Chukchi and Beaufort Seas: Annual report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Reproductive activity in the bowhead whale was observed in early May near Pt. Barrow Alaska, indicating that this species may calf and breed during the northward...

  14. Bottom Sediment Granulometric Data for the Continental Margins of the Bering, Chukchi, East Siberia, Laptev, and Beaufort Seas

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are part of Roberts, Richard W., University of Washington, Department of Oceanography Special Report No. 70, Bottom Sediment Granulometric Data for the...

  15. 77 FR 10711 - Safety Zone; KULLUK, Outer Continental Shelf Mobile Offshore Drilling Unit (MODU), Beaufort Sea, AK

    Science.gov (United States)

    2012-02-23

    ... Federal Register (73 FR 3316). Public Meeting The Coast Guard does not plan to hold a public meeting. But... of the vessel located at the coordinates listed in Table 1. These coordinates are based upon UTM...

  16. Final environmental impact statement, Beaufort Sea oil and gas development/Northstar Project. Volume 2: Chapters 1 through 4

    International Nuclear Information System (INIS)

    BP Exploration (Alaska) Inc. (BPXA) submitted a permit application to the US Army Engineer District, Alaska (Corps) to initiate the review process for BPXA's plans to develop and produce oil and gas from the Northstar Unit. The Corps determined that issuance of a permit for BPXA's proposed project constituted a major federal action that may significant affect the quality of the human environment pursuant to the National Environmental Policy Act (NEPA). In addition, the US Environmental Protection Agency (EPA), upon review of BPXA's permit application, determined under provisions of the Clean Water Act and 40 CFR Part 6 Subpart F that permitting for BPXA's proposed project constituted a major federal action that may significantly affect the quality of the human environment. As a result, preparation of an Environmental Impact Statement (EIS) under NEPA was undertaken to identify and evaluate a range of reasonable alternatives and evaluate the potential effects the alternatives, including BPXA's proposed project, may have on the human environment

  17. Final environmental impact statement, Beaufort Sea oil and gas development/Northstar Project. Appendices L through P

    International Nuclear Information System (INIS)

    BP Exploration (Alaska) Inc. (BPXA) submitted a permit application to the US Army Engineer District, Alaska to initiate the review process for BPXA's plans to develop and produce oil and gas from the Northstar Unit. This report contains Appendices L-P of an Environmental Impact Statement which was undertaken to identify and evaluate the potential effects the proposed project may have on the environment

  18. Final environmental impact statement, Beaufort Sea oil and gas development/Northstar Project. Volume 1: Executive summary

    International Nuclear Information System (INIS)

    BP Exploration (Alaska) Inc. (BPXA) submitted a permit application to comply with Section 404 of the Clean Water Act and Section 10 of the Rivers and Harbors Act to the US Army Engineer District, Alaska (Corps). The application initiated the review process for BPXA's proposed project to develop and produce oil and gas from the Northstar Unit. The National Environmental Policy Act (NEPA) requires preparation of an Environmental Impact Statement (EIS) prior to any federal action that may significantly affect the quality of the human environment. The EIS is intended to provide federal agencies with information about the consequences of a proposed project and to disclose that information to the public, soliciting their comments, prior to the agencies making decisions on the project

  19. Final environmental impact statement, Beaufort Sea oil and gas development/Northstar Project. Volume 3: Chapters 5 through 7

    International Nuclear Information System (INIS)

    BP Exploration (Alaska) Inc. (BPXA) submitted a permit application to the US Army Engineer District, Alaska to initiate the review process for BPXA's plans to develop and produce oil and gas from the Northstar Unit. This report contains chapters 5--7 of an Environmental Impact Statement which was undertaken to identify and evaluate the potential effects the proposed project may have on the environment. Attention is focused on the effects of oil on the physical, biological, and human environments

  20. Final environmental impact statement, Beaufort Sea oil and gas development/Northstar Project. Volume 4: Chapters 8 through 13

    International Nuclear Information System (INIS)

    BP Exploration (Alaska) Inc. (BPXA) submitted a permit application to the US Army Engineer District, Alaska to initiate the review process for BPXA's plans to develop and produce oil and gas from the Northstar Unit. This report contains chapters 8--13 of an Environmental Impact Statement which was undertaken to identify and evaluate the potential effects the proposed project may have on the environment. Attention is focused on the following: effects of oil on the physical, biological, and human environments; effects of noise on the biological and human environments; cumulative effects on the environment; and comparison of project alternatives and their impacts

  1. AFSC/NMML: Marine Mammal Aerial Surveys in the Bering, Chukchi and Beaufort Seas . 1979-2014

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Bureau of Ocean Energy Management (BOEM), formerly the Minerals Management Service (MMS), and its precursor, the Bureau of Land Management, have funded aerial...

  2. 77 FR 38718 - Safety Zone; NOBLE DISCOVERER, Outer Continental Shelf Drillship, Chukchi and/or Beaufort Seas, AK

    Science.gov (United States)

    2012-06-29

    ... Register (77 FR 10707). The NPRM included a 30-day comment period. We received 3 (three) submissions with... sensitivity of the environmental and subsistence importance to the indigenous population; (4) the lack of any... drilling activities may not be on July 1, 2012. The Coast Guard agrees and is amending language relating...

  3. 77 FR 39164 - Safety Zone; KULLUK, Outer Continental Shelf Mobile Offshore Drilling Unit (MODU), Beaufort Sea, AK

    Science.gov (United States)

    2012-07-02

    ... Federal Register (77 FR 10711). The NPRM included a 30- day comment period. We received 2 (two... environment given the sensitivity of the environmental and subsistence importance to the indigenous population... not be on July 1, 2012. The Coast Guard agrees and is amending language in the preamble relating...

  4. The 'interior' shelves of the Arctic Ocean: Physical oceanographic setting, climatology and effects of sea-ice retreat on cross-shelf exchange

    Science.gov (United States)

    Williams, William J.; Carmack, Eddy C.

    2015-12-01

    The interior shelves of the Arctic Mediterranean are the shelves of the Kara Sea, Laptev Sea, East Siberian Sea and Beaufort Sea. They comprise approximately 40% of the total arctic shelf area (∼2.5 × 106 km2) and are distinguished from inflow and outflow shelves by their principal forcing dynamics. Along their southern (continental) boundary the interior shelves are dominated by the major arctic rivers, receiving over 80% of the total freshwater input to the Arctic Ocean. In the mid-shelf region wind and ice motion surface stresses dominate mixing and circulation, resulting in high variability. Along, their northern (seaward) boundary they are forced by upwelling- and downwelling-favourable surface stresses which drive shelf-basin exchanges with Atlantic- and Pacific-origin cyclonic boundary currents over the upper slope. Shelf-basin exchange is further modified by shelf-break morphometry (e.g. canyons, valleys, headlands and bottom slope). Here we review the physical oceanographic settings and forcing of the interior shelves and then focus on shelfbreak exchange and supply of nutrients for new primary production due to upwelling across the shelfbreak. As a proxy for this nutrient supply, we show seasonal and annual time series of along-shelfbreak surface-stress due to wind and ice motion from 1979 to 2011. We apply this analysis to the shallow shelves from the Kara Sea to the Beaufort Sea and comment on recent increases due to atmospheric changes and sea-ice retreat.

  5. Relating Regional Arctic Sea Ice and climate extremes over Europe

    Science.gov (United States)

    Ionita-Scholz, Monica; Grosfeld, Klaus; Lohmann, Gerrit; Scholz, Patrick

    2016-04-01

    The potential increase of temperature extremes under climate change is a major threat to society, as temperature extremes have a deep impact on environment, hydrology, agriculture, society and economy. Hence, the analysis of the mechanisms underlying their occurrence, including their relationships with the large-scale atmospheric circulation and sea ice concentration, is of major importance. At the same time, the decline in Arctic sea ice cover during the last 30 years has been widely documented and it is clear that this change is having profound impacts at regional as well as planetary scale. As such, this study aims to investigate the relation between the autumn regional sea ice concentration variability and cold winters in Europe, as identified by the numbers of cold nights (TN10p), cold days (TX10p), ice days (ID) and consecutive frost days (CFD). We analyze the relationship between Arctic sea ice variation in autumn (September-October-November) averaged over eight different Arctic regions (Barents/Kara Seas, Beaufort Sea, Chukchi/Bering Seas, Central Arctic, Greenland Sea, Labrador Sea/Baffin Bay, Laptev/East Siberian Seas and Northern Hemisphere) and variations in atmospheric circulation and climate extreme indices in the following winter season over Europe using composite map analysis. Based on the composite map analysis it is shown that the response of the winter extreme temperatures over Europe is highly correlated/connected to changes in Arctic sea ice variability. However, this signal is not symmetrical for the case of high and low sea ice years. Moreover, the response of temperatures extreme over Europe to sea ice variability over the different Arctic regions differs substantially. The regions which have the strongest impact on the extreme winter temperature over Europe are: Barents/Kara Seas, Beaufort Sea, Central Arctic and the Northern Hemisphere. For the years of high sea ice concentration in the Barents/Kara Seas there is a reduction in the number

  6. Tensile strength of multi-year pressure ridge sea ice samples

    Energy Technology Data Exchange (ETDEWEB)

    Cox, G.F.N.; Richter-Menge, J.A.

    1985-09-01

    Thirty-six constant strain-rate uniaxial tension tests were performed on vertically oriented multi-year pressure ridge samples from the Beaufort Sea. The tests were performed on a closed-loop electro-hydraulic testing machine at two strain rates (10 V and 10 T s ) and two temperatures (-20 and -5 C). This paper summarizes the sample preparation and testing techniques used in the investigation and presents data on the tensile strength, initial tangent modulus, and failure strain of the ice.

  7. Temporal and spatial variability in sea-ice carbon:nitrogen ratios on Canadian Arctic shelves

    Directory of Open Access Journals (Sweden)

    Andrea Niemi

    2015-12-01

    Full Text Available Abstract To enhance the accuracy of carbon cycling models as applied to sea ice in the changing Arctic, we analyzed a large data set of particulate organic carbon (POC and nitrogen (PON measurements in first-year bottom sea ice (n = 257 from two Arctic shelves, the Canadian Arctic Archipelago and Beaufort Sea shelf, including dark winter and spring seasonal measurements. Wide ranges of sea-ice POC:PON ratios were observed during both the dark winter (12–46 mol:mol and spring (3–24 mol:mol periods. Sea-ice POC:PON ratios and chlorophyll a concentrations were significantly higher in the Archipelago versus the Beaufort Sea shelf (p < 0.01, yet there was a highly significant relationship between sea-ice POC and PON during spring for both shelves (r2 = 0.94. POC:PON ratios were not consistent over the range of measured POC and PON concentrations, justifying the use of a power function model to best describe the relationship between POC and PON. Distinct relationships between POC:PON ratios and chlorophyll-based biomass were observed for the dark winter and the spring: dark winter sea-ice POC:PON ratios decreased with increasing sea-ice biomass whereas spring POC:PON ratios increased with increasing sea-ice biomass. The transition from the dark period to the spring growth period in first-year sea ice represented a distinct stoichiometric shift in POC:PON ratios. Our results demonstrate that the Redfield ratio has limited applicability over the four-order of magnitude range of biomass concentrations observed in first-year sea ice on Arctic shelves. This study emphasizes the need for variable POC:PON stoichiometry in sea-ice biogeochemical models and budget estimates, in particular at high biomass concentrations and when considering seasonality outside of the spring period in first year ice. The use of a power function model for POC:PON relationships in sea ice is also recommended to better constrain carbon estimates in biogeochemical sea-ice models.

  8. Flume experiments on permeability and organic matter as related to the genesis of uranium deposits in the Beaufort Group

    International Nuclear Information System (INIS)

    The size, shape, and grade of uranium deposits in the Beaufort Group was controlled primarily by the distribution of plant debris and the permeability of the host sediments at the time of mineralization. A natural sand, similar to the mineralized sandstone, was studied under different hydrodynamic conditions in a flume to determine the causes of local variations in these two factors. Linguoid small ripples, sinuous dunes, and upper flow regime plane beds were formed under vertical accretion conditions. The concentration of organics was controlled by local flow patterns over the respective bedforms and was inversely related to the current velocity. The permeability of the sand was a direct exponential function of its grain size, but sorting and the presence of absence of lamination influenced the permeability of the coarse and fine fractions respectively. In all cases, the lowest permeability was recorded in the vertical direction across the laminae, whereas measurements in the horizontal plane, normal to the current, generally showed the highest permeability. The experimental results confirm certain field observations on the distribution of uranium in the Beaufort Group and provide insight into some of the underlying ore controls. 8 figs., 8 tabs., 13 refs

  9. Stability Zone of Natural Gas Hydrates in a Permafrost-Bearing Region of the Beaufort-Mackenzie Basin: Study of a Feasible Energy Source (Geological Survey of Canada Contribution No.1999275)

    International Nuclear Information System (INIS)

    Analysis of geological and geophysical data from 150 wells in the Beaufort-Mackenzie region(study area between 68 deg. 30'-70 deg. 00'N and 131 deg. -39 deg. W) led to reinterpretation of the depth of methane hydrate stability and construction of the first contour maps displaying thickness of hydrate stability zones as well as hydrate stability zone thicknesses below permafrost. Calculations were based on construction of temperature-depth profiles incorporating regional heat-flow values, temperature at the base of ice-bearing permafrost, and models relating thermal conductivity with depth. Data analysis indicates the presence and extent of the methane hydrate stability zone is related mainly to the history of permafrost development and less so by the relatively small regional variations of temperature gradients. Analysis of well logs and other indicators in conjunction with knowledge of the hydrate stability zone allows reevaluation of the location of possible gas hydrate occurrences. Log analysis indicates that in the onshore and shallow sea area of the Beaufort-Mackenzie Basin, methane hydrate occurs in 27 wells. Fifteen of these locations coincides with underlying conventional hydrocarbon occurrences. Previous analyses place some of the hydrate occurrences at greater depths than proposed for the methane hydrate stability zone described in this study. Interpretation of geological cross sections reveals that hydrates are related mainly to sandy deltaic and delta-plain deposits in Iperk, Kugmallit, and Reindeer sequences although additional hydrate picks have been inferred in other sequences, such as Richards. Overlying permafrost may act as seal for hydrate accumulations; however, the thickness of permafrost and its related hydrate stability zone fluctuated during geological time. It is interpreted that only in the last tens of thousand of years (i.e., Sangamonian to Holocene), conditions for hydrates changed from nonstable to stable. During Early and Late

  10. The delivery of organic contaminants to the Arctic food web: Why sea ice matters

    DEFF Research Database (Denmark)

    Pucko, M.; Stern, Gary; Macdonald, Robie;

    2015-01-01

    For decades sea ice has been perceived as a physical barrier for the loading of contaminants to the Arctic Ocean. We show that sea ice, in fact, facilitates the delivery of organic contaminants to the Arctic marine food web through processes that: 1) are independent of contaminant physical......–chemical properties (e.g. 2–3-fold increase in exposure to brine-associated biota), and 2) depend on physical–chemical properties and, therefore, differentiate between contaminants (e.g. atmospheric loading of contaminants to melt ponds over the summer, and their subsequent leakage to the ocean). We estimate...... the concentrations of legacy organochlorine pesticides (OCPs) and current-use pesticides (CUPs) in melt pond water in the Beaufort Sea, Canadian High Arctic, in 2008, at near-gas exchange equilibriumbased on Henry's lawconstants (HLCs), air concentrations and exchange dynamics. CUPs currently present the highest...

  11. Spatial and temporal variations in the age structure of Arctic sea ice

    Science.gov (United States)

    Belchansky, G.I.; Douglas, D.C.; Platonov, N.G.

    2005-01-01

    Spatial and temporal variations in the age structure of Arctic sea ice are investigated using a new reverse chronology algorithm that tracks ice-covered pixels to their location and date of origin based on ice motion and concentration data. The Beaufort Gyre tends to harbor the oldest (>10 years old) sea ice in the western Arctic while direct ice advection pathways toward the Transpolar Drift Stream maintain relatively young (10 years old (10+ year age class) were observed during 1989-2003. Since the mid-1990s, losses to the 10+ year age class lacked compensation by recruitment due to a prior depletion of all mature (6-10 year) age classes. Survival of the 1994 and 1996-1998 sea ice generations reestablished most mature age classes, and thereby the potential to increase extent of the 10+ year age class during the mid-2000s.

  12. Evaluation of Arctic Sea Ice Thickness Simulated by AOMIP Models

    Science.gov (United States)

    Johnson, Mark; Proshutinsky, Andrey; Aksenov, Yevgeny; Nguyen, An T.; Lindsay, Ron; Haas, Christian; Zhang, Jinlun; Diansky, Nimolay; Kwok, Ron; Maslowski, Wieslaw; Hakkinen, Sirpa; Ashik, Igor; de Cuevas, Beverly

    2011-01-01

    We compare results from six AOMIP model simulations with estimates of sea ice thickness obtained from ICESat, moored and submarine-based upward looking sensors, airborne electromagnetic measurements and drill holes. Our goal is to find patterns of model performance to guide model improvement. The satellite data is pan-arctic from 2004-2008, ice-draft data is from moored instruments in Fram Strait, the Greenland Sea and the Beaufort Sea from 1992-2008 and from submarines from 1975-2000. The drill hole data are from the Laptev and East Siberian marginal seas from 1982-1986 and from coastal stations from 1998-2009. While there are important caveats when comparing modeled results with measurements from different platforms and time periods such as these, the models agree well with moored ULS data. In general, the AOMIP models underestimate the thickness of measured ice thicker than about 2 m and overestimate thickness of ice thinner than 2 m. The simulated results are poor over the fast ice and marginal seas of the Siberian shelves. Averaging over all observational data sets, the better correlations and smaller differences from observed thickness are from the ECCO2 and UW models.

  13. Marine bird specimen and other data from the Beaufort/Simpson Lagoon as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 25 June 1978 to 23 September 1978 (NODC Accession 8000051)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine bird specimen and other data were collected from the Beaufort/Simpson Lagoon from 25 June 1978 to 23 September 1978. Data were collected by the Alaska...

  14. Solar radiation interactions with seasonal sea ice

    Science.gov (United States)

    Ehn, Jens Kristian

    Presently, the Arctic Ocean is undergoing an escalating reduction in sea ice and a transition towards a seasonal sea ice environment. This warrants detailed investigations into improving our understanding of the seasonal evolution of sea ice and snow covers, and their representation in climate models. The interaction of solar radiation with sea ice is an important process influencing the energy balance and biological activity in polar seas, and consequently plays a key role in the earth's climate system. This thesis focuses on characterization of the optical properties---and the underlying physical properties that determine them---of seasonal sea ice during the fall freeze-up and the spring melt periods. Both periods display high spatial heterogeneity and rapid temporal changes in sea ice properties, and are therefore poorly understood. Field data were collected in Amundsen Gulf/Franklin Bay (FB), southern-eastern Beaufort Sea, in Oct.-Nov. 2003 and Apr. 2004 and in Button Bay (BB), western Hudson Bay, in Mar.-May 2005 to address (1) the temporal and spatial evolution of surface albedo and transmittance, (2) how radiative transfer in sea ice is controlled by its physical nature, and (3) the characteristics of the bottom ice algae community and its effect on the optical properties. The fall study showed the importance of surface features such as dry or slushy bare ice, frost flowers and snow cover in determining the surface albedo. Ice thickness was also important, however, mostly because surface features were associated with thickness. For example, nilas (snow layer as snow grains were dissolved or merged with the salty and warm brine skim layer on the surface, while surface conditions on thicker ice types were cold and dry enough to support a snow cover. In general, the surface albedo increased exponentially with an ice thickness increase, however, variability within ice thickness types were very large. It is apparent that a more complete treatment of brine

  15. Random Seas

    DEFF Research Database (Denmark)

    Liu, Z.; Frigaard, Peter

    Sea waves are the most important phenomenon to be considering in the design of coastal and offshore structures.......Sea waves are the most important phenomenon to be considering in the design of coastal and offshore structures....

  16. Seasonality of Air-sea-ice-land Variables for Arctic Tundra in Northern Eurasia and North America

    Science.gov (United States)

    Bhatt, U. S.; Walker, D. A.; Raynolds, M. K.; Steele, M.; Epstein, H.; Jia, G.; Comiso, J. C.; Pinzon, J. E.; Tucker, C. J.

    2009-12-01

    The strength of tundra productivity trends as measured by the annual maximum Normalized Difference Vegetation Index (MaxNDVI) and time integrated NDVI (TI-NDVI) vary around the Arctic over the 1982-2008 period. Our analysis suggests that the timing of terrestrial vegetation growth is connected to seasonal patterns of sea-ice concentrations, ocean temperatures and land surface temperatures. This study used SSMI estimates of sea ice concentration, based on a bootstrap algorithm and AVHRR radiometric surface temperature. Summer Warmth Index (SWI) was calculated as the sum from May to August of the degree months above freezing of surface temperature at each pixel and is an accepted measure of plant growth potential. The Normalized Difference Vegetation Index (NDVI) represents vegetation greenness and has been used extensively to monitor changes in the Arctic. The albedo of green plants varies with solar radiation wavelength, which is the basis for the NDVI index. The analysis was conducted within 50 km of the Arctic coastline to focus on the region of maximum maritime influence. Time series of regional sea-ice concentration, SWI and NDVI were constructed for the 50-km width domains for the Pan-Arctic, North America, Eurasia and Arctic subregions. Standard climate analysis techniques were applied to the regional time series to investigate the seasonality of sea ice, NDVI and SWI. MaxNDVI has increased in the 50-km land domain contiguous to the Beaufort Sea by 17% since 1982, whereas it has only increased by 3% in the coastal Kara Sea region. Analysis of semimonthly MaxNDVI indicates that the vegetation greens up more rapidly in the spring in the Beaufort than the W. Kara and the Kara has slightly higher NDVI in the fall. The climatological weekly sea ice concentrations in 50-km coastal domain displays an earlier breakup in the Beaufort and a later freeze-up in the Kara Sea area. Regional differences in the seasonal cycle can in part explain the spatially varied trends

  17. Optical properties of melting first-year Arctic sea ice

    Science.gov (United States)

    Light, Bonnie; Perovich, Donald K.; Webster, Melinda A.; Polashenski, Christopher; Dadic, Ruzica

    2015-11-01

    The albedo and transmittance of melting, first-year Arctic sea ice were measured during two cruises of the Impacts of Climate on the Eco-Systems and Chemistry of the Arctic Pacific Environment (ICESCAPE) project during the summers of 2010 and 2011. Spectral measurements were made for both bare and ponded ice types at a total of 19 ice stations in the Chukchi and Beaufort Seas. These data, along with irradiance profiles taken within boreholes, laboratory measurements of the optical properties of core samples, ice physical property observations, and radiative transfer model simulations are employed to describe representative optical properties for melting first-year Arctic sea ice. Ponded ice was found to transmit roughly 4.4 times more total energy into the ocean, relative to nearby bare ice. The ubiquitous surface-scattering layer and drained layer present on bare, melting sea ice are responsible for its relatively high albedo and relatively low transmittance. Light transmittance through ponded ice depends on the physical thickness of the ice and the magnitude of the scattering coefficient in the ice interior. Bare ice reflects nearly three-quarters of the incident sunlight, enhancing its resiliency to absorption by solar insolation. In contrast, ponded ice absorbs or transmits to the ocean more than three-quarters of the incident sunlight. Characterization of the heat balance of a summertime ice cover is largely dictated by its pond coverage, and light transmittance through ponded ice shows strong contrast between first-year and multiyear Arctic ice covers.

  18. Ecosystem dynamics of the Pacific-influenced Northern Bering and Chukchi Seas in the Amerasian Arctic

    Science.gov (United States)

    Grebmeier, Jacqueline M.; Cooper, Lee W.; Feder, Howard M.; Sirenko, Boris I.

    2006-10-01

    The shallow continental shelves and slope of the Amerasian Arctic are strongly influenced by nutrient-rich Pacific waters advected over the shelves from the northern Bering Sea into the Arctic Ocean. These high-latitude shelf systems are highly productive both as the ice melts and during the open-water period. The duration and extent of seasonal sea ice, seawater temperature and water mass structure are critical controls on water column production, organic carbon cycling and pelagic-benthic coupling. Short food chains and shallow depths are characteristic of high productivity areas in this region, so changes in lower trophic levels can impact higher trophic organisms rapidly, including pelagic- and benthic-feeding marine mammals and seabirds. Subsistence harvesting of many of these animals is locally important for human consumption. The vulnerability of the ecosystem to environmental change is thought to be high, particularly as sea ice extent declines and seawater warms. In this review, we focus on ecosystem dynamics in the northern Bering and Chukchi Seas, with a more limited discussion of the adjoining Pacific-influenced eastern section of the East Siberian Sea and the western section of the Beaufort Sea. Both primary and secondary production are enhanced in specific regions that we discuss here, with the northern Bering and Chukchi Seas sustaining some of the highest water column production and benthic faunal soft-bottom biomass in the world ocean. In addition, these organic carbon-rich Pacific waters are periodically advected into low productivity regions of the nearshore northern Bering, Chukchi and Beaufort Seas off Alaska and sometimes into the East Siberian Sea, all of which have lower productivity on an annual basis. Thus, these near shore areas are intimately tied to nutrients and advected particulate organic carbon from the Pacific influenced Bering Shelf-Anadyr water. Given the short food chains and dependence of many apex predators on sea ice, recent

  19. Contrasting patterns of river runoff and sea-ice melted water in the Canada Basin

    Institute of Scientific and Technical Information of China (English)

    TONG Jinlu; CHEN Min; QIU Yusheng; LI Yanping; CAO Jianping

    2014-01-01

    The fractions of river runoff and sea-ice melted water in the Canada Basin in summer 2003 were determined by the salinity-δ18O system. The fraction of river runoff (fR) was high in the upper 50 m of the water column and decreased with depth and latitude. The signals of the river runoff were confined to water depths above 200 m. The total amount of river runoff in the Canada Basin was higher than that in other arctic seas, indi-cating that the Canada Basin is a main storage region for river runoff. The penetration depth of the sea-ice melted water was less than 50 m to the south of 78°N, while it was about 150 m to the north of 78°N. The total amount of sea-ice melted water was much higher to the north of 78°N than to the south of 78°N, indicating the sea-ice melted waters accumulated on the ice edge. The abundant sea-ice melted water on the ice edge was attributed to the earlier melted water in the southern Canada Basin and transported by the Beaufort Gyre or the reinforced melting of sea ice by solar radiation in the polynya.

  20. Geology and mineral resources of the Florence, Beaufort, Rocky Mount, and Norfolk 10 x 20 NTMS quadrangles. National Uranium Resource Evaluation program

    International Nuclear Information System (INIS)

    This document provides geologic and mineral resources data for previously-issued Savannah River Laboratory hydrogeochemical and stream sediment reports of the Beaufort, Florence, Norfolk, and Rocky Mount 10 x 20 National Topographic Map Series quadrangles in the southeastern United States. This report is issued in draft form, without detailed technical and copy editing. This was done to make the report available to the public before the end of the National Uranium Resource Evaluation program

  1. The delivery of organic contaminants to the Arctic food web: why sea ice matters.

    Science.gov (United States)

    Pućko, Monika; Stern, Gary A; Macdonald, Robie W; Jantunen, Liisa M; Bidleman, Terry F; Wong, Fiona; Barber, David G; Rysgaard, Søren

    2015-02-15

    For decades sea ice has been perceived as a physical barrier for the loading of contaminants to the Arctic Ocean. We show that sea ice, in fact, facilitates the delivery of organic contaminants to the Arctic marine food web through processes that: 1) are independent of contaminant physical-chemical properties (e.g. 2-3-fold increase in exposure to brine-associated biota), and 2) depend on physical-chemical properties and, therefore, differentiate between contaminants (e.g. atmospheric loading of contaminants to melt ponds over the summer, and their subsequent leakage to the ocean). We estimate the concentrations of legacy organochlorine pesticides (OCPs) and current-use pesticides (CUPs) in melt pond water in the Beaufort Sea, Canadian High Arctic, in 2008, at near-gas exchange equilibrium based on Henry's law constants (HLCs), air concentrations and exchange dynamics. CUPs currently present the highest risk of increased exposures through melt pond loading and drainage due to the high ratio of melt pond water to seawater concentration (Melt pond Enrichment Factor, MEF), which ranges from 2 for dacthal to 10 for endosulfan I. Melt pond contaminant enrichment can be perceived as a hypothetical 'pump' delivering contaminants from the atmosphere to the ocean under ice-covered conditions, with 2-10% of CUPs annually entering the Beaufort Sea via this input route compared to the standing stock in the Polar Mixed Layer of the ocean. The abovementioned processes are strongly favored in first-year ice compared to multi-year ice and, therefore, the dynamic balance between contaminant inventories and contaminant deposition to the surface ocean is being widely affected by the large-scale icescape transition taking place in the Arctic. PMID:25437762

  2. Deep versus shallow controlling factors of the regional thermal field in the Beaufort-Mackenzie Basin (Arctic Canada)

    Science.gov (United States)

    Scheck-Wenderoth, M.; Sippel, J.; Lewerenz, B.

    2011-12-01

    The present-day temperature distribution of the Beaufort-Mackenzie Basin as observed in boreholes indicates large-scale thermal anomalies which have been related to specific tectonic domains and heat transported by convection along major discontinuities (Chen et al., 2008). We have integrated seismic and well data into a crust-scale 3D structural model of the basin, which we have additionally constrained by 3D gravity modelling. This structural model is composed of seven Mesozoic-Cenozoic tectonostratigraphic units which - as a result of a complex foreland depositional and erosional history - tend to be younger, less compacted, and thus less thermally conductive towards the north. The underlying continental crust comprises a low-density upper part (2720 kg/m3 ) and a moderately dense lower part (2850 kg/m3), and it thins considerably towards the north where it passes over to oceanic crust (2900 kg/m2 ). We use the structural model to calculate the 3D conductive thermal field of the basin based on a Finite-Element method, thereby taking one step further towards a quantification of heat transporting processes in this petroliferous region. For the validation of the modelling results, we make use of public domain temperature data from more than 230 wells reaching depths of up to 5000 m. Thermal conductivities are assigned to the different units according to available data sets including also the observed lithology-dependent relationship between conductivity and porosity in the region. The upper boundary condition for the thermal calculations is provided by the well-known depth distribution of the base of permafrost (0 °C isotherm). Assuming a constant heat flow of 30 mW/m2 at the Moho, we find that the modelled temperatures are widely consistent with the observed temperatures in most parts of the basin. Only where large tectonic discontinuities structure the margins of the basin, the misfits are considerable, thus indicating convective heat transport to be an

  3. Air-sea interactions in the marginal ice zone

    Directory of Open Access Journals (Sweden)

    Seth Zippel

    2016-03-01

    Full Text Available Abstract The importance of waves in the Arctic Ocean has increased with the significant retreat of the seasonal sea-ice extent. Here, we use wind, wave, turbulence, and ice measurements to evaluate the response of the ocean surface to a given wind stress within the marginal ice zone, with a focus on the local wind input to waves and subsequent ocean surface turbulence. Observations are from the Beaufort Sea in the summer and early fall of 2014, with fractional ice cover of up to 50%. Observations showed strong damping and scattering of short waves, which, in turn, decreased the wind energy input to waves. Near-surface turbulent dissipation rates were also greatly reduced in partial ice cover. The reductions in waves and turbulence were balanced, suggesting that a wind-wave equilibrium is maintained in the marginal ice zone, though at levels much less than in open water. These results suggest that air-sea interactions are suppressed in the marginal ice zone relative to open ocean conditions at a given wind forcing, and this suppression may act as a feedback mechanism in expanding a persistent marginal ice zone throughout the Arctic.

  4. ICESat: Sea ice freeboard, snow depth, and thickness

    Science.gov (United States)

    Kwok, R.

    2007-12-01

    Total freeboard (snow and ice) and thickness of the Arctic Ocean sea ice cover are derived from ICESat data for two 35-day periods: one during the fall (Oct-Nov) of 2005 and the other during the winter (Feb-Mar) of 2006. Our freeboard retrieval approach is based on reflectivity and the expected statistics of freeboard variability from combined analysis of RADARSAT/ICESat data. Results suggest that our retrieval procedures could provide consistent freeboard estimates along 25-km segments with uncertainties of better than several centimeters. With a climatology of snow density, ECMWF snowfall is used to construct a time-varying field of snow depth for the conversion of freeboard to sea ice thickness. The derived ice thickness estimates are compared with ice draft observations from moored upward looking sonar data and the snow depth/thickness data from mass balance buoys in the Beaufort Sea. Preliminary results show that the estimated ICESat thickness estimates are within 0.5 m of the ice drafts reported by moorings. In this talk, we highlight some of the issues associated with the process of freeboard retrieval, thickness estimation, and quality assessment due to the disparity of spatial resolution between the ICESat footprint and those from in-situ measurements.

  5. Seasonal evolution of melt ponds on Arctic sea ice

    Science.gov (United States)

    Webster, Melinda A.; Rigor, Ignatius G.; Perovich, Donald K.; Richter-Menge, Jacqueline A.; Polashenski, Christopher M.; Light, Bonnie

    2015-09-01

    The seasonal evolution of melt ponds has been well documented on multiyear and landfast first-year sea ice, but is critically lacking on drifting, first-year sea ice, which is becoming increasingly prevalent in the Arctic. Using 1 m resolution panchromatic satellite imagery paired with airborne and in situ data, we evaluated melt pond evolution for an entire melt season on drifting first-year and multiyear sea ice near the 2011 Applied Physics Laboratory Ice Station (APLIS) site in the Beaufort and Chukchi seas. A new algorithm was developed to classify the imagery into sea ice, thin ice, melt pond, and open water classes on two contrasting ice types: first-year and multiyear sea ice. Surprisingly, melt ponds formed ˜3 weeks earlier on multiyear ice. Both ice types had comparable mean snow depths, but multiyear ice had 0-5 cm deep snow covering ˜37% of its surveyed area, which may have facilitated earlier melt due to its low surface albedo compared to thicker snow. Maximum pond fractions were 53 ± 3% and 38 ± 3% on first-year and multiyear ice, respectively. APLIS pond fractions were compared with those from the Surface Heat Budget of the Arctic Ocean (SHEBA) field campaign. APLIS exhibited earlier melt and double the maximum pond fraction, which was in part due to the greater presence of thin snow and first-year ice at APLIS. These results reveal considerable differences in pond formation between ice types, and underscore the importance of snow depth distributions in the timing and progression of melt pond formation.

  6. Evaluation of Arctic Sea Ice Thickness Simulated by Arctic Ocean Model Intercomparison Project Models

    Science.gov (United States)

    Johnson, Mark; Proshuntinsky, Andrew; Aksenov, Yevgeny; Nguyen, An T.; Lindsay, Ron; Haas, Christian; Zhang, Jinlun; Diansky, Nikolay; Kwok, Ron; Maslowski, Wieslaw; Hakkinen, Sirpa; Ashik, Igor; De Cuevas, Beverly

    2012-01-01

    Six Arctic Ocean Model Intercomparison Project model simulations are compared with estimates of sea ice thickness derived from pan-Arctic satellite freeboard measurements (2004-2008); airborne electromagnetic measurements (2001-2009); ice draft data from moored instruments in Fram Strait, the Greenland Sea, and the Beaufort Sea (1992-2008) and from submarines (1975-2000); and drill hole data from the Arctic basin, Laptev, and East Siberian marginal seas (1982-1986) and coastal stations (1998-2009). Despite an assessment of six models that differ in numerical methods, resolution, domain, forcing, and boundary conditions, the models generally overestimate the thickness of measured ice thinner than approximately 2 mand underestimate the thickness of ice measured thicker than about approximately 2m. In the regions of flat immobile landfast ice (shallow Siberian Seas with depths less than 25-30 m), the models generally overestimate both the total observed sea ice thickness and rates of September and October ice growth from observations by more than 4 times and more than one standard deviation, respectively. The models do not reproduce conditions of fast ice formation and growth. Instead, the modeled fast ice is replaced with pack ice which drifts, generating ridges of increasing ice thickness, in addition to thermodynamic ice growth. Considering all observational data sets, the better correlations and smaller differences from observations are from the Estimating the Circulation and Climate of the Ocean, Phase II and Pan-Arctic Ice Ocean Modeling and Assimilation System models.

  7. Seasonal sea ice predictions for the Arctic based on assimilation of remotely sensed observations

    Science.gov (United States)

    Kauker, F.; Kaminski, T.; Ricker, R.; Toudal-Pedersen, L.; Dybkjaer, G.; Melsheimer, C.; Eastwood, S.; Sumata, H.; Karcher, M.; Gerdes, R.

    2015-10-01

    The recent thinning and shrinking of the Arctic sea ice cover has increased the interest in seasonal sea ice forecasts. Typical tools for such forecasts are numerical models of the coupled ocean sea ice system such as the North Atlantic/Arctic Ocean Sea Ice Model (NAOSIM). The model uses as input the initial state of the system and the atmospheric boundary condition over the forecasting period. This study investigates the potential of remotely sensed ice thickness observations in constraining the initial model state. For this purpose it employs a variational assimilation system around NAOSIM and the Alfred Wegener Institute's CryoSat-2 ice thickness product in conjunction with the University of Bremen's snow depth product and the OSI SAF ice concentration and sea surface temperature products. We investigate the skill of predictions of the summer ice conditions starting in March for three different years. Straightforward assimilation of the above combination of data streams results in slight improvements over some regions (especially in the Beaufort Sea) but degrades the over-all fit to independent observations. A considerable enhancement of forecast skill is demonstrated for a bias correction scheme for the CryoSat-2 ice thickness product that uses a spatially varying scaling factor.

  8. Reduced body size and cub recruitment in polar bears associated with sea ice decline

    Science.gov (United States)

    Rode, K.D.; Amstrup, Steven C.; Regehr, E.V.

    2010-01-01

    Rates of reproduction and survival are dependent upon adequate body size and condition of individuals. Declines in size and condition have provided early indicators of population decline in polar bears (Ursus maritimus) near the southern extreme of their range. We tested whether patterns in body size, condition, and cub recruitment of polar bears in the southern Beaufort Sea of Alaska were related to the availability of preferred sea ice habitats and whether these measures and habitat availability exhibited trends over time, between 1982 and 2006. The mean skull size and body length of all polar bears over three years of age declined over time, corresponding with long-term declines in the spatial and temporal availability of sea ice habitat. Body size of young, growing bears declined over time and was smaller after years when sea ice availability was reduced. Reduced litter mass and numbers of yearlings per female following years with lower availability of optimal sea ice habitat, suggest reduced reproductive output and juvenile survival. These results, based on analysis of a longterm data set, suggest that declining sea ice is associated with nutritional limitations that reduced body size and reproduction in this population. ?? 2010 by the Ecological Society of America.

  9. Less winter cloud aids summer 2013 Arctic sea ice return from 2012 minimum

    International Nuclear Information System (INIS)

    In September 2012, Arctic sea ice cover reached a record minimum for the satellite era. The following winter the sea ice quickly returned, carrying through to the summer when ice extent was 48% greater than the same time in 2012. Most of this rebound in the ice cover was in the Chukchi and Beaufort Seas, areas experiencing the greatest decline in sea ice over the last three decades. A variety of factors, including ice dynamics, oceanic and atmospheric heat transport, wind, and solar insolation anomalies, may have contributed to the rebound. Here we show that another factor, below-average Arctic cloud cover in January–February 2013, resulted in a more strongly negative surface radiation budget, cooling the surface and allowing for greater ice growth. More thick ice was observed in March 2013 relative to March 2012 in the western Arctic Ocean, and the areas of ice growth estimated from the negative cloud cover anomaly and advected from winter to summer with ice drift data, correspond well with the September ice concentration anomaly pattern. Therefore, decreased wintertime cloud cover appears to have played an important role in the return of the sea ice cover the following summer, providing a partial explanation for large year-to-year variations in an otherwise decreasing Arctic sea ice cover. (paper)

  10. Prevalence and Antibiogram Profiling of Escherichia coli Pathotypes Isolated from the Kat River and the Fort Beaufort Abstraction Water

    Directory of Open Access Journals (Sweden)

    Nolonwabo Nontongana

    2014-08-01

    Full Text Available Escherichia coli is a widespread bacterium encompassing a variety of strains, ranging from highly pathogenic strains, causing worldwide outbreaks of severe diseases to avirulent, well characterized safe laboratory strains. This study evaluated the prevalence and antibiogram profiles of E. coli pathotypes isolated from the Kat River and Fort Beaufort abstraction water. A total of 171 out of 278 confirmed E. coli isolates were positive for at least one pathogenic determinant and these included enteropathogenic E. coli (6%, enterotoxigenic E. coli (47%, uropathogenic E. coli (2%, neonatal meningitis E. coli (5%, diffusely adherent E. coli (1% and enterohaemorrhagic E. coli (1%. Interestingly, enteroinvasive and enteroaggregative E. coli were not detected. The phenotypic antibiogram profiles of the isolates revealed that all were resistant to penicillin G, while 98% and 38% of the pathotypes were resistant to ampicillin and trimethoprim-sulphamethoxazole, respectively. About 8% of the isolates were resistant to streptomycin. More than half of the isolates exhibited multiple antibiotic resistance with 44% being resistant to three antibiotics and 8% resistant to four antibiotics. We conclude that the Kat River is a reservoir of potentially virulent antibiotic resistant E. coli strains that can cause serious health risks to humans who drink raw water from this river, or in the case that consumption of treated drinking water coincides with failed drinking water processes.

  11. Dynamics of an idealized Beaufort Gyre: 1. The effect of a small beta and lack of western boundaries

    Science.gov (United States)

    Yang, Jiayan; Proshutinsky, Andrey; Lin, Xiaopei

    2016-02-01

    The Beaufort Gyre in the Arctic Ocean differs from a typical moderate-latitude gyre in some major aspects of its dynamics. First, it is located in a basin without a western boundary, which is essential for closing midlatitude circulations. Second, the gradient in Coriolis parameter, β, is small and so the validity of the Sverdrup balance is uncertain. In this paper, we use an idealized two-layer model to examine several processes that are related to these two issues. In a circular basin with closed geostrophic contours in interior, the variability of vorticity in the upper layer is dominated by eddies. But in the time-mean circulation, the main dynamical balance in the basin's interior is between the curl of wind stress and the eddy vorticity fluxes. The torque of friction becomes important along the boundary where the rim current is strong. It is found that the smallness of β has only a relatively small impact in a circular basin without a meridional boundary. The gyre is considerably more sensitive to the existence of a meridional boundary. The time-mean circulation weakens considerably when a peninsula is inserted between the model's center and the rim. (One side of the peninsula is dynamically equivalent to a midlatitude western boundary.) The gyre's sensitivity to β has also increased significantly when a meridional boundary is present. Subsurface ridges have similar effects on the gyre as a boundary, indicating that such topographic features may substitute, to some extents, the dynamical role of a western boundary.

  12. Study of Impacts of Arctic Sea Ice Reduction on Atmospheric Chemical Processes - The BROMEX 2012 Field Campaign

    Science.gov (United States)

    Nghiem, S. V.

    2012-12-01

    Arctic perennial sea ice has decreased drastically in the last decade and still remained low in spring 2012 as observed from scatterometer datasets acquired by QuikSCAT and Oceansat-2 satellites. In particular, the thinner, weaker, and saltier seasonal sea ice has dominated over the perennial ice in the Chukchi Sea and Beaufort Sea. To investigate impacts of sea ice reduction on atmospheric chemical processes, we conducted the BRomine, Ozone, and Mercury EXperiment in (BROMEX) in March-April 2012 around Barrow, extending out to a large region offshore and inland. Here we present overview results from BROMEX, which was successfully carried out by about 30 scientists, researchers, and field workers from multiple international institutions. For BROMEX, we coordinated and collected satellite data, including a number of near-real-time products, from multiple satellite instruments including MODIS, AMSR-E, GOME-2, SCIAMACHY, OMI, RADARSAT-2, Envisat ASAR, TanDEM-X, SMOS, CryoSat-2, and Oceansat-2. Over the BROMEX field region, we made measurements and collected sea ice, snow, ocean, and air samples for physical, meteorological, chemical, biological, and acoustic studies. A helicopter was used to deploy chemical and meteorological buoys in the Chukchi Sea and the Beaufort Sea. Measurements were also made with airborne sensors across sea ice, leads, lagoon, and tundra along various flight patterns of the ALAR aircraft. Furthermore, we coordinated with the NASA IceBridge P3 aircraft to collect surface temperature, surface height, snow depth, and ice thickness measurements. We set up and maintained field sites on sea ice and in the tundra to measure bromine, ozone, mercury, and other chemical species. Moreover, we obtained temperature data from many different types of temperature sensors for temperature accuracy assessment to identify potential issues that might cause errors or biases in temperature measurements. An enormous amount of in-situ snow and ice data was collected

  13. Arctic Sea Ice Thickness - Past, Present And Future

    Science.gov (United States)

    Wadhams, P.

    2007-12-01

    In November 2005 the International Workshop on Arctic Sea Ice Thickness: Past, Present and Future was held at Rungstedgaard Conference Center, near Copenhagen, Denmark. The proceedings of the Workshop were subsequently published as a book by the European Commission. In this review we summarise the conclusions of the Workshop on the techniques which show the greatest promise for thickness monitoring on different spatial and temporal scales, and for different purposes. Sonic methods, EM techniques, buoys and satellite methods will be considered. Some copies of the book will be available at the lecture, and others can be ordered from the European Commission. The paper goes on to consider early results from some of the latest measurements on Arctic sea ice thickness done in 2007. These comprise a trans-Arctic voyage by a UK submarine, HMS "Tireless", equipped with a Kongsberg 3002 multibeam sonar which generates a 3-D digital terrain map of the ice underside; and experiments at the APLIS ice station in the Beaufort Sea carried out by the Gavia AUV equipped with a GeoSwath interferometric sonar. In both cases 3-D mapping of sea ice constitutes a new step forward in sea ice data collection, but in the case of the submarine the purpose is to map change in ice thickness (comparing results with a 2004 "Tireless" cruise and with US and UK data prior to 2000), while for the small AUV the purpose is intensive local mapping of a few ridges to improve our knowledge of their structure, as part of a multisensor programme

  14. Variations in the Arctic's multiyear sea ice cover: A neural network analysis of SMMR-SSM/I data, 1979-2004

    Science.gov (United States)

    Belchansky, Gennady I.; Douglas, David C.; Eremeev, Vladimir A.; Platonov, Nikita G.

    2005-05-01

    A 26-year (1979-2004) observational record of January multiyear sea ice distributions, derived from neural network analysis of SMMR-SSM/I passive microwave satellite data, reveals dense and persistent cover in the central Arctic basin surrounded by expansive regions of highly fluctuating interannual cover. Following a decade of quasi equilibrium, precipitous declines in multiyear ice area commenced in 1989 when the Arctic Oscillation shifted to a pronounced positive phase. Although extensive survival of first-year ice during autumn 1996 fully replenished the area of multiyear ice, a subsequent and accelerated decline returned the depletion to record lows. The most dramatic multiyear sea ice declines occurred in the East Siberian, Chukchi, and Beaufort Seas.

  15. Seasonal variations in sea ice motion and effects on sea ice concentration in the Canada Basin

    Science.gov (United States)

    Serreze, Mark C.; Barry, Roger G.; McLaren, Alfred S.

    1989-08-01

    Drifting buoy data, surface pressure, and geostrophic wind analyses from the Arctic Ocean Buoy Program are used to examine seasonal features of the sea ice motion in the Canada Basin for 1979-1985. Although the 7-year annual mean motion in this region is clockwise, the month-to-month motion is highly variable. In late summer to early autumn, the circulation can become net anticlockwise for periods lasting at least 30 days. Results from a linear model demonstrate that these "reversals" of ice motion in the Beaufort Gyre are a wind-driven response to persistent cyclonic activity that contrasts sharply with the predominantly anticyclonic regimes of spring, late autumn, and winter. Model-predicted ice divergences of 0.5% or more per day which can occur during periods of anticlockwise ice motion are in good agreement with values calculated from optimally interpolated velocity gradient fields. Visible band imagery and passive microwave data confirm associated large areal reductions in ice concentration of approximately 20%. Data from under-ice submarine sonar transects and surface pressure records prior to the study period point to frequent recurrences of these late summer to early autumn ice conditions.

  16. The effect of changing sea ice on the physical vulnerability of Arctic coasts

    Directory of Open Access Journals (Sweden)

    K. R. Barnhart

    2014-09-01

    Full Text Available Sea ice limits the interaction of the land and ocean water in the Arctic winter and influences this interaction in the summer by governing the fetch. In many parts of the Arctic, the open-water season is increasing in duration and summertime sea-ice extents are decreasing. Sea ice provides a first-order control on the physical vulnerability of Arctic coasts to erosion, inundation, and damage to settlements and infrastructures by ocean water. We ask how the changing sea-ice cover has influenced coastal erosion over the satellite record. First, we present a pan-Arctic analysis of satellite-based sea-ice concentration specifically along the Arctic coasts. The median length of the 2012 open-water season, in comparison to 1979, expanded by between 1.5 and 3-fold by Arctic Sea sector, which allows for open water during the stormy Arctic fall. Second, we present a case study of Drew Point, Alaska, a site on the Beaufort Sea, characterized by ice-rich permafrost and rapid coastal-erosion rates, where both the duration of the open-water season and distance to the sea-ice edge, particularly towards the northwest, have increased. At Drew Point, winds from the northwest result in increased water levels at the coast and control the process of submarine notch incision, the rate-limiting step of coastal retreat. When open-water conditions exist, the distance to the sea ice edge exerts control on the water level and wave field through its control on fetch. We find that the extreme values of water-level setup have increased consistently with increasing fetch.

  17. Sea Ice

    Science.gov (United States)

    Perovich, D.; Gerland, S.; Hendricks, S.; Meier, Walter N.; Nicolaus, M.; Richter-Menge, J.; Tschudi, M.

    2013-01-01

    During 2013, Arctic sea ice extent remained well below normal, but the September 2013 minimum extent was substantially higher than the record-breaking minimum in 2012. Nonetheless, the minimum was still much lower than normal and the long-term trend Arctic September extent is -13.7 per decade relative to the 1981-2010 average. The less extreme conditions this year compared to 2012 were due to cooler temperatures and wind patterns that favored retention of ice through the summer. Sea ice thickness and volume remained near record-low levels, though indications are of slightly thicker ice compared to the record low of 2012.

  18. Sea level change

    Digital Repository Service at National Institute of Oceanography (India)

    Church, J.A.; Clark, P.U.; Cazenave, A.; Gregory, J.M.; Jevrejeva, S.; Levermann, A.; Merrifield, M.A.; Milne, G.A.; Nerem, R.S.; Nunn, P.D.; Payne, A.J.; Pfeffer, W.T.; Stammer, D.; Unnikrishnan, A.S.

    This chapter considers changes in global mean sea level, regional sea level, sea level extremes, and waves. Confidence in projections of global mean sea level rise has increased since the Fourth Assessment Report (AR4) because of the improved...

  19. Impact of ice temperature on microwave emissivity of thin newly formed sea ice

    Science.gov (United States)

    Hwang, Byong Jun; Ehn, Jens K.; Barber, David G.

    2008-02-01

    This study examines the impact of ice temperature on microwave emissivity over thin, newly formed sea ice at 6, 19, and 37 GHz during October 2003 in the southern Beaufort Sea, where the physical properties of newly formed sea ice were coincidently measured with microwave emissions. Six ice stations with distinct properties were selected and divided according to ice surface temperature into warm (above -3°C) or cold (below -3°C) stations. The warm stations had a lower emissivity at the vertical polarization by 0.1 than the cold stations and a corresponding difference in brine volume and dielectric properties. Significant correlations were observed between brine volume and ice emissivity (R2 = 0.8, p value emissivity between warm and cold stations. The results suggest that the temperature of thin bare ice could be the critical factor in determining ice emissivity near the melting point (about -2°C). Furthermore, a slight decrease in ice temperature (i.e., from -2° to -5°C) significantly reduces the brine volume, thus resulting in high ice emissivity. Finally, we demonstrate the potential of newly formed ice to cause errors in estimating sea ice concentrations using Advanced Microwave Scanning Radiometer-E data.

  20. Sea level trends in Southeast Asian seas

    OpenAIRE

    M. W. Strassburg; B. D. Hamlington; R. R. Leben; P. Manurung; J. Lumban Gaol; B. Nababan; Vignudelli, S.; Kim, K.-Y.

    2015-01-01

    Southeast Asian seas span the largest archipelago in the global ocean and provide a complex oceanic pathway connecting the Pacific and Indian oceans. The Southeast Asian sea regional sea level trends are some of the highest observed in the modern satellite altimeter record that now spans almost 2 decades. Initial comparisons of global sea level reconstructions find that 17-year sea level trends over the past 60 years exhibit good agreement with decadal variability associated...

  1. Identification, documentation and delineation of coastal migratory bird habitat in Alaska. II, Feeding habits of birds in the Beaufort Sea: Partial final report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The impact of oil and gas development on bird populations is usually thought of in terms of spilled oil directly oiling birds and causing mortality. Far more...

  2. Alkane, terpene and polycyclic aromatic hydrocarbon geochemistry of the Mackenzie River and Mackenzie shelf: Riverine contributions to Beaufort Sea coastal sediment

    Science.gov (United States)

    Yunker, Mark B.; Macdonald, Robie W.; Cretney, Walter J.; Fowler, Brian R.; McLaughlin, Fiona A.

    1993-07-01

    To study the largest source of river sediment to the Arctic Ocean, we have collected suspended particulates from the Mackenzie River in all seasons and sediments from the Mackenzie shelf between the river mouth and the shelf edge. These samples have been analyzed for alkanes, triterpenes and polycyclic aromatic hydrocarbons (PAHs). We found that naturally occurring hydrocarbons predominate in the river and on the shelf. These hydrocarbons include biogenic alkanes and triterpenes with a higher plant/peat origin, diagenetic PAHs from peat and plant detritus, petrogenic alkanes, triterpenes and PAHs from oil seeps and/or bitumens and combustion PAHs that are likely relict in peat deposits. Because these components vary independently, the season is found to strongly influence the concentration and composition of hydrocarbons in the Mackenzie River. While essentially the same pattern of alkanes, diagenetic hopanes and alkyl PAHs is observed in all river and most shelf sediment samples, alkane and triterpene concentration variations are strongly linked to the relative amount of higher plant/peat material. Polycyclic aromatic hydrocarbon molecular-mass profiles also appear to be tied primarily to varying proportions of peat, with an additional petrogenic component which is most likely associated with lithic material mobilized by the Mackenzie River at freshet. Consistent with the general lack of alkyl PAHs in peat, the higher PAHs found in the river are probably derived from forest and tundra fires. A few anthropogenic/pyrogenic compounds are manifest only at the shelf edge, probably due to a weakening of the river influence. We take this observation of pyrogenic PAHs and the pronounced source differences between two sediment samples collected at the shelf edge as evidence of a transition from dominance by the Mackenzie River to the geochemistry prevalent in Arctic regions far removed from major rivers.

  3. Biogeographic provinces of total and methyl mercury in zooplankton and fish from the Beaufort and Chukchi seas: results from the SHEBA drift.

    Science.gov (United States)

    Stern, G A; MacDonald, R W

    2005-07-01

    Samples of copepods (Calanus hyperboreus) and arctic cod (Boreogadus saida) were collected along the SHEBA (Surface HEat Budget of the Arctic) drift track, which commenced in the Canada Basin (October 1997) and finished in the Mendeleev Basin (October 1998). Here, we report total mercury (HgT) and CH3Hg concentrations in these biological samples and examine concentration variability along the drift track in the context of trophic variation, inputs from land, spring mercury depletion events (MDEs), and oceanographic provinces. We find background concentrations of HgT in C. hyperboreus as low as 0.02 microg/g (dw), with the Canada Basin samples exhibiting approximately 2-fold higher mercury concentrations than those from the Chukchi Plateau and Mendeleev Abyssal Plain. This east-to-west trend in mercury concentration is punctuated by two and possibly three intervals of elevated mercury (HgT, 0.10-0.12 microg/g (dw); CH3Hg, 0.023-0.028 microg/g (dw)) along the drift track. One interval of elevated HgT and CH3-Hg levels occurred during and shortly after melt. %CH3Hg reached a maximum of 60% during this time period, three times higher than any other time during the drift. This transient rise in C. hyperboreus CH3Hg concentration seems to strongly point to mercury accumulated in snow during MDEs. However, the alignment of elevated mercury samples with oceanographic fronts and the observed regional differences between basins suggest that variation of mercury concentration is primarily a consequence of ocean structure. Given that large animals such as whales selectively forage in regions of higher food concentration such as fronts, recent change in the ice climate of the western Arctic Ocean, perhaps mediated by changes in heat storage, may provide the means to change their exposure to mercury thus explaining observed increases in mercury concentrations in western beluga whales during the 1990s. PMID:16053067

  4. Ecosystem function and particle flux dynamics across the Mackenzie Shelf (Beaufort Sea, Arctic Ocean): an integrative analysis of spatial variability and biophysical forcings

    OpenAIRE

    Forest, A.; Babin, M.; Stemmann, L; Picheral, M.; Sampei, M.; Fortier, L; Gratton, Y.; Bélanger, S.; Devred, E.; J. Sahlin; Doxaran, D; Joux, F.; E. Ortega-Retuerta; Jeffrey, W H; Martín, J.

    2012-01-01

    A better understanding of how environmental changes affect organic matter fluxes in Arctic marine ecosystems is sorely needed. Here, we combine mooring times-series, ship-based measurements and remote-sensing to assess the variability and forcing factors of vertical fluxes of particulate organic carbon (POC) across the Mackenzie Shelf in 2009. We developed a geospatial model of these fluxes to proceed to an integrative analysis of their biophysical determinants in summer. Flux data were ...

  5. Ecosystem function and particle flux dynamics across the Mackenzie Shelf (Beaufort Sea, Arctic Ocean: an integrative analysis of spatial variability and biophysical forcings

    Directory of Open Access Journals (Sweden)

    A. Forest

    2013-05-01

    Full Text Available A better understanding of how environmental changes affect organic matter fluxes in Arctic marine ecosystems is sorely needed. Here we combine mooring times series, ship-based measurements and remote sensing to assess the variability and forcing factors of vertical fluxes of particulate organic carbon (POC across the Mackenzie Shelf in 2009. We developed a geospatial model of these fluxes to proceed to an integrative analysis of their determinants in summer. Flux data were obtained with sediment traps moored around 125 m and via a regional empirical algorithm applied to particle size distributions (17 classes from 0.08–4.2 mm measured by an Underwater Vision Profiler 5. The low fractal dimension (i.e., porous, fluffy particles derived from the algorithm (1.26 ± 0.34 and the dominance (~ 77% of rapidly sinking small aggregates (p r2 cum. = 0.37. Bacteria were correlated with small aggregates, while northeasterly wind was associated with large size classes (> 1 mm ESD, but these two factors were weakly related with each other. Copepod biomass was overall negatively correlated (p < 0.05 with vertical POC fluxes, implying that metazoans acted as regulators of export fluxes, even if their role was minor given that our study spanned the onset of diapause. Our results demonstrate that on interior Arctic shelves where productivity is low in mid-summer, localized upwelling zones (nutrient enrichment may result in the formation of large filamentous phytoaggregates that are not substantially retained by copepod and bacterial communities.

  6. Ecosystem function and particle flux dynamics across the Mackenzie Shelf (Beaufort Sea, Arctic Ocean): an integrative analysis of spatial variability and biophysical forcings

    OpenAIRE

    Forest, A.; Babin, M.; Stemmann, L; Picheral, M.; Sampei, M.; Fortier, L; Gratton, Y.; Bélanger, S.; Devred, E.; J. Sahlin; Doxaran, D; Joux, F.; E. Ortega-Retuerta; Martín, J.; Jeffrey, W H

    2013-01-01

    A better understanding of how environmental changes affect organic matter fluxes in Arctic marine ecosystems is sorely needed. Here we combine mooring times series, ship-based measurements and remote sensing to assess the variability and forcing factors of vertical fluxes of particulate organic carbon (POC) across the Mackenzie Shelf in 2009. We developed a geospatial model of these fluxes to proceed to an integrative analysis of their determinants in summer. Flux data were ...

  7. Ecosystem function and particle flux dynamics across the Mackenzie Shelf (Beaufort Sea, Arctic Ocean): an integrative analysis of spatial variability and biophysical forcings

    Science.gov (United States)

    Forest, A.; Babin, M.; Stemmann, L.; Picheral, M.; Sampei, M.; Fortier, L.; Gratton, Y.; Bélanger, S.; Devred, E.; Sahlin, J.; Doxaran, D.; Joux, F.; Ortega-Retuerta, E.; Martín, J.; Jeffrey, W. H.; Gasser, B.; Miquel, J. Carlos

    2013-05-01

    A better understanding of how environmental changes affect organic matter fluxes in Arctic marine ecosystems is sorely needed. Here we combine mooring times series, ship-based measurements and remote sensing to assess the variability and forcing factors of vertical fluxes of particulate organic carbon (POC) across the Mackenzie Shelf in 2009. We developed a geospatial model of these fluxes to proceed to an integrative analysis of their determinants in summer. Flux data were obtained with sediment traps moored around 125 m and via a regional empirical algorithm applied to particle size distributions (17 classes from 0.08-4.2 mm) measured by an Underwater Vision Profiler 5. The low fractal dimension (i.e., porous, fluffy particles) derived from the algorithm (1.26 ± 0.34) and the dominance (~ 77%) of rapidly sinking small aggregates ( 1 mm ESD), but these two factors were weakly related with each other. Copepod biomass was overall negatively correlated (p < 0.05) with vertical POC fluxes, implying that metazoans acted as regulators of export fluxes, even if their role was minor given that our study spanned the onset of diapause. Our results demonstrate that on interior Arctic shelves where productivity is low in mid-summer, localized upwelling zones (nutrient enrichment) may result in the formation of large filamentous phytoaggregates that are not substantially retained by copepod and bacterial communities.

  8. Periodic bowhead whale aerial surveys by the USDI/Minerals Management Service in the Bering, Chukchi and Beaufort Seas, April 1979 - October 2001 (NODC Accession 0001139)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Minerals Management Service (MMS), previously Bureau of Land Management, has funded fall bowhead whale aerial surveys in this area each year since 1978, using a...

  9. AFSC/NMML: Acoustics long-term passive monitoring using moored autonomous recorders in the Bering, Chukchi, and Western Beaufort Seas, 2007-2012

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Marine Mammal Laboratory (NMML) has deployed long-term passive acoustic recorders in various locations in Alaskan waters and in the High Arctic to...

  10. Final environmental impact statement, Beaufort Sea oil and gas development/Northstar Project. Appendix A: BP Exploration (Alaska) Inc. Final project description - Revision 1, March 27, 1997

    International Nuclear Information System (INIS)

    BP Exploration (Alaska) Inc. (BPXA) submitted a permit application to the US Army Engineer District, Alaska to initiate the review process for BPXA's plans to develop and produce oil and gas from the Northstar Unit. This report contains Appendix A of an Environmental Impact Statement which was undertaken to identify and evaluate the potential effects the proposed project may have on the environment. This document is the Northstar Development Project, Final Project Description, Revision 1 for BPXA Northstar Project

  11. Physical forcings and intense shelf-slope fluxes of particulate matter in the halocline waters of the Canadian Beaufort Sea during winter

    Science.gov (United States)

    Forest, Alexandre; Osborne, Philip D.; Fortier, Louis; Sampei, Makoto; Lowings, Malcolm G.

    2015-06-01

    Resolving the mechanisms that support the transfer of particulate matter across the shelf-slope interface is a key issue for the sustainable development of marine resources along continental margins. A better comprehension of shelf-slope exchanges is particularly needed in the Arctic Ocean given the intensification of human activities and rapid environmental changes in this region. Here, we use three years of physical and biogeochemical data collected with tautline moorings deployed from September 2009 to August 2012 over the slope of the Mackenzie Shelf to identify the processes that drive the lateral transport of particulate matter off the shelf. The main dataset consists of particle flux time-series collected with automated sediments traps deployed on moorings at ~80 and ~180 m depth over the mid-slope. We detected a strong vertical discrepancy in the magnitude of particulate mass fluxes that were 20-600% higher at ~180 m than at ~80 m, and up to ~1500% greater during the winter season alone. The high fluxes at ~180 m depth were linked to several sedimentation events occurring from November to May each year, which were not captured by the upper ~80 m traps. These differences corroborate previous studies that documented active transport of resuspended material near the bottom across the shelf-break and in the mid-water column over the slope. Consideration of particle fluxes along with synchronous current time-series, water column properties and meteorological data revealed that thermohaline convection and storm winds act as the main mechanisms underlying resuspension and transport processes. Their combination drives mesoscale eddy formation, downwelling flows and current surges that are characterized by moderate to high velocities (~20-80 cm s-1) sufficient to mobilize sediments. Turbidity near the shelf-break and particle fluxes over the slope were particularly enhanced in winter 2011 (mass fluxes up to ~2 g m-2 d-1) when a persistent downwelling-favorable wind regime and a large production of winter water were observed. Overall, the amount of winter water events correlated significantly (R2=0.76) with the magnitude of mass fluxes collected at ~180 m. Our analysis revealed a complex pattern of mean currents over the slope facilitating instabilities, frontal structures, shear and eddying motion. Additional work is needed on erosion mechanisms in the bottom boundary layer and their relationship to regional and mesoscale circulation and eddy activity over the upper slope.

  12. Migratory bird use of the coastal lagoon system of the Beaufort Sea coastline within the Arctic National Wildlife Refuge, Alaska, 1981 and 1982

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report describes aerial surveys conducted in coastal lagoons of the Arctic National Wildlife Refuge during 1982 to obtain an index of relative numbers of...

  13. Bowhead Whale Feeding Ecology Study (BOWFEST): Aerial Survey in Chukchi and Beaufort Seas conducted from 2007-08-23 to 2011-09-16 (NCEI Accession 0131425)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Bowhead Whale Feeding Ecology Study (BOWFEST) was initiated in May 2007 through an Interagency Agreement between the Bureau of Ocean Energy Management (BOEM)...

  14. Effects of changing sea ice on marine mammals and subsistence hunters in northern Alaska from traditional knowledge interviews.

    Science.gov (United States)

    Huntington, Henry P; Quakenbush, Lori T; Nelson, Mark

    2016-08-01

    Marine mammals are important sources of food for indigenous residents of northern Alaska. Changing sea ice patterns affect the animals themselves as well as access to them by hunters. Documenting the traditional knowledge of Iñupiaq and Yupik hunters concerning marine mammals and sea ice makes accessible a wide range of information relevant to understanding the ecosystem to which humans belong. We interviewed hunters in 11 coastal villages from the northern Bering Sea to the Beaufort Sea. Hunters reported extensive changes in sea ice and weather that have affected the timing of marine mammal migrations, their distribution and behaviour and the efficacy of certain hunting methods. Amidst these changes, however, hunters cited offsetting technological benefits, such as more powerful and fuel-efficient outboard engines. Other concerns included potential impacts to subsistence hunting from industrial activity such as shipping and oil and gas development. While hunters have been able to adjust to some changes, continued environmental changes and increased disturbance from human activity may further challenge their ability to acquire food in the future. There are indications, however, that innovation and flexibility provide sources of resilience. PMID:27555644

  15. Trends in the breeding population of Adelie penguins in the Ross Sea, 1981-2012: a coincidence of climate and resource extraction effects.

    Directory of Open Access Journals (Sweden)

    Phil O'B Lyver

    Full Text Available Measurements of the size of Adélie penguin (Pygoscelis adeliae colonies of the southern Ross Sea are among the longest biologic time series in the Antarctic. We present an assessment of recent annual variation and trends in abundance and growth rates of these colonies, adding to the published record not updated for more than two decades. High angle oblique aerial photographic surveys of colonies were acquired and penguins counted for the breeding seasons 1981-2012. In the last four years the numbers of Adélie penguins in the Ross and Beaufort Island colonies (southern Ross Sea metapopulation reached their highest levels since aerial counts began in 1981. Results indicated that 855,625 pairs of Adélie penguins established breeding territories in the western Ross Sea, with just over a quarter (28% of those in the southern portion, constituting a semi-isolated metapopulation (three colonies on Ross Island, one on nearby Beaufort Island. The southern population had a negative per capita growth rate of -0.019 during 1981-2000, followed by a positive per capita growth rate of 0.067 for 2001-2012. Colony growth rates for this metapopulation showed striking synchrony through time, indicating that large-scale factors influenced their annual growth. In contrast to the increased colony sizes in the southern population, the patterns of change among colonies of the northern Ross Sea were difficult to characterize. Trends were similar to southern colonies until the mid-1990s, after which the signal was lost owing to significantly reduced frequency of surveys. Both climate factors and recovery of whale populations likely played roles in the trends among southern colonies until 2000, after which depletion of another trophic competitor, the Antarctic toothfish (Dissostichus mawsoni, may explain the sharp increasing trend evident since then.

  16. 福州市螺洲大桥主桥钢箱梁顶推施工技术%Fuzhou Beaufort Bridge Pushing steel box girder construction technology

    Institute of Scientific and Technical Information of China (English)

    黄强

    2011-01-01

    Bridge project with Fuzhou Beaufort introduced Pushing walker pan features and construction techniques of process equipment,and the use of centralized control system.At the same time according to the actual situation of this project,analysis of the top platform and push the design of temporary buttress will not rationality and economy.%结合福州市螺洲大桥工程介绍步履式平移顶推施工技术的特点和工艺设备,以及采用的集中控制系统。同时根据本工程实际情况,分析顶推平台与临时支墩的布置与设计的合理性以及经济性。

  17. An algorithm to detect sea ice leads using AMSR-E passive microwave imagery

    Directory of Open Access Journals (Sweden)

    J. Röhrs

    2010-02-01

    Full Text Available Leads are major sites of energy fluxes and brine releases at the air-ocean interface of sea ice covered oceans. This study presents an algorithm to detect leads that are broader than 3 km in the entire Arctic Ocean. The algorithm detected 50% of the lead area that is visible in optical satellite images. Passive microwave imagery from the Advanced Microwave Scanning Radiometer – Earth Observation System (AMSR-E is used, allowing daily observations that are independent of daylight or cloud conditions. Using unique signatures of thin ice in the brightness temperature ratio between the 89 GHz and 19 GHz channels, the algorithm allowed to detect thin ice features in the ice cover and is optimized to detect leads. Leads were mapped for the period from 2002–2009 excluding the summer months. Several frequently reoccurring large scale lead patterns were found, especially in regions where sea ice is known to drift out of the Arctic Ocean. The maximum lead occurrence in the Arctic is located in the Beaufort Sea, low lead occurrence was found in the inner Arctic Ocean close to the North Pole.

  18. Distribution of molluscan remains in the sediment of the Chukchi Sea and its vicinity, the Arctic

    Institute of Scientific and Technical Information of China (English)

    Gao Aiguo; Xu Fengshan; Sun Haiqing; Li Lon

    2003-01-01

    The result of an analysis of mollusca remains collected from the Chukchi Sea, Beaufort Sea and Bering Sea in the First Chinese National Arctic Research Expedition, from July to September,1999 is presented. Seventeen species of mollusca have been identified, which belong to two classes: Bivalvia and Gastropoda. The compositions of the mollusca are very simple. According to the distribution pattern two groups may be distinguished among molluscan species. The Pan-Arctic and circumboreal group comprises Nuculana pernula, N. radiata, Nucula bellotii, Astarte montagui, Seripes groenlandicus, Macoma calcarea, M. moesta alaskana, Liocyma fluctuosa, Mya pseudoarenaria and Turritella polaris. Three species, Cyclocardia crebricos tata, Trichotrois coronata and Argobuccinum oregonense are components of the Pan-Arctic and Pacific boreal group. With regard to feeding habits, detritus feeders dominate. There are 7 species of detritus feeders, i.e. , Nuculana pernula, N. radiata,Nucula bellotii , Macoma calcarea , M. moesta alaskana , Macoma sp. and Trichotropis coronata . Detritus feeders are dominant with regard to the numbers of species as well as to the frequency of occurrence. Macoma calcarea is the most abundant species.

  19. Landward and eastward shift of Alaskan polar bear denning associated with recent sea ice changes

    Science.gov (United States)

    Fischbach, A.S.; Amstrup, Steven C.; Douglas, D.C.

    2007-01-01

    Polar bears (Ursus maritimus) in the northern Alaska region den in coastal areas and on offshore drifting ice. We evaluated changes in the distribution of polar bear maternal dens between 1985 and 2005, using satellite telemetry. We determined the distribution of maternal dens occupied by 89 satellite collared female polar bears between 137°W and 167°W longitude. The proportion of dens on pack ice declined from 62% in 1985–1994 to 37% in 1998–2004 (P = 0.044) and among pack ice dens fewer occurred in the western Beaufort Sea after 1998. We evaluated whether hunting, attraction to bowhead whale remains, or changes in sea ice could explain changes in den distribution. We concluded that denning distribution changed in response to reductions in stable old ice, increases in unconsolidated ice, and lengthening of the melt season. In consort, these changes have likely reduced the availability and quality of pack ice denning habitat. Further declines in sea ice availability are predicted. Therefore, we expect the proportion of polar bears denning in coastal areas will continue to increase, until such time as the autumn ice retreats far enough from shore that it precludes offshore pregnant females from reaching the Alaska coast in advance of denning.

  20. The vertical distribution of buoyant plastics at sea

    Directory of Open Access Journals (Sweden)

    J. Reisser

    2014-11-01

    Full Text Available Millimeter-sized plastics are numerically abundant and widespread across the world's ocean surface. These buoyant macroscopic particles can be mixed within the upper water column due to turbulent transport. Models indicate that the largest decrease in their concentration occurs within the first few meters of water, where subsurface observations are very scarce. By using a new type of multi-level trawl at 12 sites within the North Atlantic accumulation zone, we measured concentrations and physical properties of plastics from the air–seawater interface to a depth of 5 m, at 0.5 m intervals. Our results show that plastic concentrations drop exponentially with water depth, but decay rates decrease with increasing Beaufort scale. Furthermore, smaller pieces presented lower rise velocities and were more susceptible to vertical transport. This resulted in higher depth decays of plastic mass concentration (mg m−3 than numerical concentration (pieces m−3. Further multi-level sampling of plastics will improve our ability to predict at-sea plastic load, size distribution, drifting pattern, and impact on marine species and habitats.

  1. Near Real Time Sea Ice Thickness from the CryoSat-2 Satellite, and the application of a time-varying snow load

    Science.gov (United States)

    Tilling, R.; Ridout, A.; Shepherd, A.; Muir, A.

    2015-12-01

    Since October 2010, data from the European Space Agency (ESA) CryoSat-2 (CS-2) satellite has provided the means to produce sea ice thickness maps across the entire Arctic Ocean basin. These large-scale observations of Arctic sea ice thickness are required to determine trends, compare hemispheres and aid predictive models of future global climate change. However, the final ESA data product is not available until ~30 days after the satellite acquisition, and as such the use of the data for near real time (NRT), operational purposes, has not been possible. At University College London (UCL) we now produce the first NRT estimates of Arctic sea ice thickness, with a lag of only 2 days, using NRT data that has recently been released by ESA. This original, operational dataset will benefit industries such as transport and tourism, as well as the scientific community. This presentation will summarise the NRT product and the data that is avilable, investigate the differences between the NRT and final product, and analyse its reliability and data coverage in particular regions of interest (e.g. the Northwest Passage, and the Beaufort Sea). We have also developed an Arctic-wide, time-varying snow load, so that our CryoSat-2 sea ice processing no longer relies on a constant monthly snow climatology. This presentation will summarise the development, application, and benefits of the new snow load in relation to our NRT and final sea ice thickness estimates.

  2. Biases of the Arctic climate in a regional ocean-sea ice-atmosphere coupled model:an annual validation

    Institute of Scientific and Technical Information of China (English)

    LIU Xiying

    2014-01-01

    The Coupling of three model components, WRF/PCE (polar climate extension version of weather research and forecasting model ( WRF)), ROMS (regional ocean modeling system), and CICE (community ice code), has been implemented, and the regional atmosphere-ocean-sea ice coupled model named WRF/PCE-ROMS-CICE has been validated against ERA-interim reanalysis data sets for 1989. To better understand the reasons that generate model biases, the WRF/PCE-ROMS-CICE results were compared with those of its components, the WRF/PCE and the ROMS-CICE. There are cold biases in surface air temperature (SAT) over the Arctic Ocean, which contribute to the sea ice concentration (SIC) and sea surface temperature (SST) biases in the results of the WRF/PCE-ROMS-CICE. The cold SAT biases also appear in results of the atmo-spheric component with a mild temperature in winter and similar temperature in summer. Compared to results from the WRF/PCE, due to influences of different distributions of the SIC and the SST and inclusion of interactions of air-sea-sea ice in the WRF/PCE-ROMS-CICE, the simulated SAT has new features. These influences also lead to apparent differences at higher levels of the atmosphere, which can be thought as responses to biases in the SST and sea ice extent. There are similar atmospheric responses in feature of distribution to sea ice biases at 700 and 500 hPa, and the strength of responses weakens when the pressure decreases in January. The atmospheric responses in July reach up to 200 hPa. There are surplus sea ice ex-tents in the Greenland Sea, the Barents Sea, the Davis Strait and the Chukchi Sea in winter and in the Beau-fort Sea, the Chukchi Sea, the East Siberian Sea and the Laptev Sea in summer in the ROMS-CICE. These differences in the SIC distribution can all be explained by those in the SST distributions. These features in the simulated SST and SIC from ROMS-CICE also appear in the WRF/PCE-ROMS-CICE. It is shown that the performance of the WRF/PCE-ROMS-CICE is

  3. Relative sea level and coastal environments in arctic Alaska during Marine Isotope Stage 5

    Science.gov (United States)

    Farquharson, L. M.; Mann, D. H.; Jones, B. M.; Rittenour, T. M.; Grosse, G.; Groves, P.

    2015-12-01

    Marine Isotope Stage (MIS) 5 was characterized by marked fluctuations in climate, the warmest being MIS 5e (124-119 ka) when relative sea level (RSL) stood 2-10 m higher than today along many coastlines. In northern Alaska, marine deposits now 5-10 m above modern sea level are assigned to this time period and termed the Pelukian transgression (PT). Complicating this interpretation is the possibility that an intra-Stage 5 ice shelf extended along the Alaskan coast, causing isostatic depression along its grounded margins, which caused RSL highs even during periods of low, global RSL. Here we use optically stimulated luminescence (OSL) to date inferred PT deposits on the Beaufort Sea coastal plain. A transition from what we interpret to be lagoonal mud to sandy tidal flat deposits lying ~ 2.75 m asl dates to 113+/-18 ka. Above this, a 5-m thick gravelly barrier beach dates to 95 +/- 20 ka. This beach contains well-preserved marine molluscs, whale vertebrae, and walrus tusks. Pleistocene-aged ice-rich eolian silt (yedoma) blanket the marine deposits and date to 57.6 +/-10.9 ka. Our interpretation of this chronostratigraphy is that RSL was several meters higher than today during MIS 5e, and lagoons or brackish lakes were prevalent. Gravel barrier beaches moved onshore as local RSL rose further after MIS 5e. The error range of the OSL age of the barrier-beach unit spans the remaining four substages of MIS 5; however, the highstand of RSL on this arctic coastline appears to occurr after the warmest part of the last interglacial and appears not to be coeval with the eustatic maximum reached at lower latitudes during MIS 5. One possibility is that RSL along the Beaufort Sea coast was affected by isostatic depression caused by an ice shelf associated with widespread, intra-Stage 5 glaciation that was out of phase with lower latitude glaciation and whose extent and timing remains enigmatic.

  4. Holocene Northern Hemisphere sea-ice distribution - proxy data reconstruction and modelling

    Science.gov (United States)

    Seidenkrantz, Marit-Solveig; de Vernal, Anne; Goosse, Hugues; Klein, François; Solignac, Sandrine; Van Nieuwenhove, Nicolas; Pearce, Christof; Caissie, Beth; Belt, Simon; Sha, Longbin; Cronin, Thomas M.; Stein, Rüdiger; Macias-Fauria, Marc; DeNinno, Lauren H.

    2016-04-01

    A strikingly fast decrease of Arctic sea-ice cover has been recorded for the instrumental period and attributed to anthropogenic climate change, but little is known about natural sea-ice variability. Hence, there is a need for longer sea-ice time series to establish a baseline for natural Arctic sea-ice variability. We compiled 120 proxy-based sea-ice reconstructions from the Arctic Ocean and subarctic marginal seas to evaluate the stability/variability of sea-ice cover during the Holocene. The reconstructions are primarily based on published data combined with a few yet-unpublished records of biological (diatoms, dinoflagellate cysts, foraminifera, ostracods), sedimentological (IRD), and biogeochemical (IP25, PIP25, TOC) sea-ice indicators. Each indicator and record has been interpreted independently. We present all data as long-term annual means (months of sea ice per year). Sea-ice reconstructions are grouped into these classes: perennial (11-12 month/yr), dense (6-10 m/yr), common (1-6 m/yr), occasional (0.1-1 m/yr), rare (almost never) and absent (never). Further, reconstructions are made for the time slices 0-2 cal. ka (BP), 2-4 ka, 4-6 ka, 6±0.5 ka, 6-8 ka and 8-10 ka. Our study shows that winter sea ice was present during the entire Holocene, but summer sea ice may have been somewhat reduced in some areas during the Holocene Climate Optimum (10-6 ka), with variations between basins. In the Nordic Seas and N Atlantic minimum sea-ice conditions are seen 10-6 ka, whereas in the eastern Labrador Sea minimum sea-ice occurred 6-4 ka. Since ~4 ka sea-ice cover has increased, especially in the most recent millennia. Changes are subtle, however, but nonetheless consistent. The Pacific sector of the Arctic (Bering, Chukchi, Beaufort, Laptev, Okhotsk seas) shows less variability during the Holocene, though it is noted that these records have poorer age control and resolution than those from the Atlantic sector. It is noteworthy that, within the available temporal

  5. Baltic Sea: Radionuclides

    DEFF Research Database (Denmark)

    Nielsen, Sven Poul; Lüning, Maria; Ilus, Erkki; Outola, Iisa; Ikäheimonen, Tarja; Mattila, Jukka; Herrmann, Jürgen; Kanisch, Günter; Osvath, Iolanda

    2011-01-01

    The most significant source of anthropogenic radioactivity in the Baltic Sea is fallout from the accident at the Chernobyl nuclear power plant in 1986. The second most important source is global fallout from atmospheric nuclear weapons tests carried out during the late 1950s and early 1960s. Radi...... seawater; only the Irish Sea and the Black Sea show higher levels. In 1990, average concentrations of 137Cs in fish from the Baltic Sea were similar to those in the Irish Sea, about 4 times higher than in the Black Sea and about 30 times higher than in the Mediterranean Sea....

  6. Baltic Sea: Radionuclides

    DEFF Research Database (Denmark)

    Nielsen, Sven Poul; Lüning, Maria; Ilus, Erkki; Outola, Iisa; Ikäheimonen, Tarja; Mattila, Jukka; Herrmann, Jürgen; Kanisch, Günter; Osvath, Iolanda

    2010-01-01

    The most significant source of anthropogenic radioactivity in the Baltic Sea is fallout from the accident at the Chernobyl nuclear power plant in 1986. The second most important source is global fallout from atmospheric nuclear weapons tests carried out during the late 1950s and early 1960s. Radi...... seawater; only the Irish Sea and the Black Sea show higher levels. In 1990, average concentrations of 137Cs in fish from the Baltic Sea were similar to those in the Irish Sea, about 4 times higher than in the Black Sea and about 30 times higher than in the Mediterranean Sea....

  7. Satellite and ground-based observations of patterns and seasonality of sea-ice, summer warmth, snow, and NDVI along the North America and Eurasia Arctic transects

    Science.gov (United States)

    Walker, D. A.; Epstein, H. E.; Raynolds, M. K.; Bhatt, U. S.; Bieniek, P. A.

    2011-12-01

    We analyzed vegetation, climate, and spectral data from zonal sites along two >1500 km long transects that span all five Arctic bioclimate subzones in North America and Eurasia to help interpret the long-term changes in satellite-derived trends of pattern and seasonality of vegetation greenness. Despite large differences in environment and vegetation along the two transects, there is nearly an identical logarithmic relationship between biomass and the summer maximum normalized difference vegetation index derived from AVHRR sensors (MaxNDVI) along the two transects. Summer open water in the Northern Alaska/Beaufort Sea region has increased by 39%, the summer warmth index (SWI) of the tundra increased by 14%, MaxNDVI by 28% and time-integrated NDVI (TI-NDVI) by 21%. The increased open water in the Beaufort is associated with a warming of the land and a large positive increase in the NDVI. In the eastern Kara Sea/Yamal Peninsula region, summer-fall open water has increased by 115%, the SWI decreased by -3%, MaxNDVI increased by only 6%, and TI-NDVI by 2%. The greatly reduced sea ice has affected the summer total warmth and NDVI of the Eurasia transect minimally possibly due to increased winter snow and delayed snowmelt in much of northwest Russian Arctic. In northern Alaska, there is distinctive trend of earlier snow melt at most stations; whereas the northern Yamal has seen an increase in the snow water equivalent and delayed melt on much of the Yagorsky, Yamal, Gydan, and Taimyr peninsulas. This appears to be associated with the reduction in the total summer warmth and relatively small increase in NDVI.

  8. Characterizing Arctic sea ice topography using high-resolution IceBridge data

    Science.gov (United States)

    Petty, Alek A.; Tsamados, Michel C.; Kurtz, Nathan T.; Farrell, Sinead L.; Newman, Thomas; Harbeck, Jeremy P.; Feltham, Daniel L.; Richter-Menge, Jackie A.

    2016-05-01

    We present an analysis of Arctic sea ice topography using high-resolution, three-dimensional surface elevation data from the Airborne Topographic Mapper, flown as part of NASA's Operation IceBridge mission. Surface features in the sea ice cover are detected using a newly developed surface feature picking algorithm. We derive information regarding the height, volume and geometry of surface features from 2009 to 2014 within the Beaufort/Chukchi and Central Arctic regions. The results are delineated by ice type to estimate the topographic variability across first-year and multi-year ice regimes. The results demonstrate that Arctic sea ice topography exhibits significant spatial variability, mainly driven by the increased surface feature height and volume (per unit area) of the multi-year ice that dominates the Central Arctic region. The multi-year ice topography exhibits greater interannual variability compared to the first-year ice regimes, which dominates the total ice topography variability across both regions. The ice topography also shows a clear coastal dependency, with the feature height and volume increasing as a function of proximity to the nearest coastline, especially north of Greenland and the Canadian Archipelago. A strong correlation between ice topography and ice thickness (from the IceBridge sea ice product) is found, using a square-root relationship. The results allude to the importance of ice deformation variability in the total sea ice mass balance, and provide crucial information regarding the tail of the ice thickness distribution across the western Arctic. Future research priorities associated with this new data set are presented and discussed, especially in relation to calculations of atmospheric form drag.

  9. The Effects of Changing Sea Ice on Marine Mammals and Their Hunters in Northern Alaska

    Science.gov (United States)

    Huntington, H.; Quakenbush, L.; Nelson, M.

    2015-12-01

    Marine mammals are important sources of food for indigenous residents of northern Alaska. Changing sea ice patterns affect the animals themselves as well as access by hunters. Documenting the traditional knowledge of Iñupiaq and Yupik hunters concerning marine mammals and sea ice makes accessible a wide range of information and insight relevant to ecological understanding, conservation action, and the regulation of human activity. We interviewed hunters in villages from northern Bering Sea to the Beaufort Sea, focusing on bowhead whales, walrus, and ice seals. Hunters reported extensive changes in sea ice, with resulting effects on the timing of marine mammal migrations, the distribution and behavior of the animals, and the efficacy of certain hunting methods, for example the difficulty of finding ice thick enough to support a bowhead whale for butchering. At the same time, hunters acknowledged impacts and potential impacts from changing technology such as more powerful outboard engines and from industrial activity such as shipping and oil and gas development. Hunters have been able to adapt to some changes, for example by hunting bowhead whales in fall as well as spring on St. Lawrence Island, or by focusing their hunt in a shorter period in Nuiqsut to accommodate work schedules and worse weather. Other changes, such as reduced availability of ice seals due to rapid retreat of pack ice after spring break-up, continue to defy easy responses. Continued environmental changes, increased disturbance from human activity, and the introduction of new regulations for hunting may further challenge the ability of hunters to provide food as they have done to date, though innovation and flexibility may also provide new sources of adaptation.

  10. Providing Real-time Sea Ice Modeling Support to the U.S. Coast Guard

    Science.gov (United States)

    Allard, Richard; Dykes, James; Hebert, David; Posey, Pamela; Rogers, Erick; Wallcraft, Alan; Phelps, Michael; Smedstad, Ole Martin; Wang, Shouping; Geiszler, Dan

    2016-04-01

    The Naval Research Laboratory (NRL) supported the U.S. Coast Guard Research Development Center (RDC) through a demonstration project during the summer and autumn of 2015. Specifically, a modeling system composed of a mesoscale atmospheric model, regional sea ice model, and regional wave model were loosely coupled to provide real-time 72-hr forecasts of environmental conditions for the Beaufort/Chukchi Seas. The system components included a 2-km regional Community Ice CodE (CICE) sea ice model, 15-km Coupled Ocean Atmosphere Mesoscale Prediction System (COAMPS) atmospheric model, and a 5-km regional WAVEWATCH III wave model. The wave model utilized modeled sea ice concentration fields to incorporate the effects of sea ice on waves. The other modeling components assimilated atmosphere, ocean, and ice observations available from satellite and in situ sources. The modeling system generated daily 72-hr forecasts of synoptic weather (including visibility), ice drift, ice thickness, ice concentration and ice strength for missions within the economic exclusion zone off the coast of Alaska and a transit to the North Pole in support of the National Science Foundation GEOTRACES cruise. Model forecasts graphics were shared on a common web page with selected graphical products made available via ftp for bandwidth limited users. Model ice thickness and ice drift show very good agreement compared with Cold Regions Research and Engineering Laboratory (CRREL) Ice Mass Balance buoys. This demonstration served as a precursor to a fully coupled atmosphere-ocean-wave-ice modeling system under development. National Ice Center (NIC) analysts used these model data products (CICE and COAMPS) along with other existing model and satellite data to produce the predicted 48-hr position of the ice edge. The NIC served as a liaison with the RDC and NRL to provide feedback on the model predictions. This evaluation provides a baseline analysis of the current models for future comparison studies

  11. Increased Arctic Sea Ice Drift Alters Polar Bear Movements and Energetics

    Science.gov (United States)

    Douglas, D. C.; Durner, G. M.; Albeke, S. E.; Whiteman, J. P.; Amstrup, S. C.; Richardson, E.; Wilson, R. R.; Ben-David, M.

    2015-12-01

    Recent thinning of Arctic sea ice has increased its drift from currents and winds. Increased ice drift could affect movements and energy balance of polar bears (Ursus maritimus) which rely, almost exclusively, on this substrate for hunting seals. Foraging by polar bears is a relatively sedentary behavior, as they typically capture their main prey by waiting at breathing holes, where seals haul-out along leads, or by short-distance stalking. We examined the response of polar bears to ice drift in the Beaufort (BS) and Chukchi (CS) seas, and between two periods with different sea ice characteristics: 1987-1998 and 1999-2013. We used satellite-tracked adult female polar bear locations, standardized by a continuous-time correlated random walk, coupled with modeled ice drift, to estimate displacement and drift-corrected bear movements along east-west and north-south axes. Sea ice drift in both regions increased with greater westward and more extreme northward and southward rates from 1987-1998 to 1999-2013. Polar bears responded with greater eastward movements and, in the CS greater movements north and south. We show that efforts by polar bears to compensate for greater westward ice drift in recent years translated into a model-derived estimate of 5.7-7.2% increase in energy expenditure. We also estimated that polar bears increased their travel time 18-20% between the two time periods, suggesting time allocated to foraging was reduced. Increased energetic costs and travel time resulting from greater ice drift, in conjunction with ongoing habitat loss, suggest that recent changes to Arctic sea ice may affect movements and energy balance of polar bears.

  12. Marine transgression, shoreline emergence: Evidence in seabed and terrestrial ground temperatures of changing relative sea levels, Arctic Canada

    Science.gov (United States)

    Taylor, Alan E.

    1991-04-01

    Precise temperatures to depths of several hundred meters have been measured in abandoned petroleum exploration wells in coastal and offshore areas of the Canadian Arctic. In these regions, changes in relative sea level during the Quaternary have left a strong thermal signature on deep ground temperatures. Surface temperature changes of the order of 10-20 K accompanied shoreline emergence due to uplift in some regions and marine transgression due to eustatic changes in sea levels in others. Classical, analytic techniques are used to demonstrate that these anomalous features are a direct consequence of recent changes in sea level. In coastal areas of the Queen Elizabeth Islands, modelling of the large, near-surface temperature-depth gradients and the distinct curvature in the measured profiles yield emergence times in general agreement with dates taken from emergence curves. The analysis suggests that surface temperatures of these coastal areas were 16-19 K higher than at present from the Late Wisconsinan until emergence in the Holocene, suggesting either marine conditions for this period or glacial ice cover with basal temperatures near the pressure melting point. In contrast, at two offshore wells on the Beaufort Shelf, analyses of the negative temperature-depth gradients below the seabed and profile curvature yield times of marine transgression generally consistent with the published sea level curve for the area. The analyses suggest that surface temperatures of some present offshore areas were 10-16 K lower than today's sea bottom temperatures from the Late Wisconsinan until marine transgression in the Holocene. The characteristic ground temperature profiles measured in such arctic areas provide independent evidence for the relative changes in sea level indicated by proxy data. It is especially valuable for these areas, where there is little historical record and from which datable material, such as shells, driftwood, and pumice fragments, may be scarce or

  13. Consequences of long-distance swimming and travel over deep-water pack ice for a female polar bear during a year of extreme sea ice retreat

    Science.gov (United States)

    Durner, G.M.; Whiteman, J.P.; Harlow, H.J.; Amstrup, Steven C.; Regehr, E.V.; Ben-David, M.

    2011-01-01

    Polar bears (Ursus maritimus) prefer to live on Arctic sea ice but may swim between ice floes or between sea ice and land. Although anecdotal observations suggest that polar bears are capable of swimming long distances, no data have been available to describe in detail long distance swimming events or the physiological and reproductive consequences of such behavior. Between an initial capture in late August and a recapture in late October 2008, a radio-collared adult female polar bear in the Beaufort Sea made a continuous swim of 687 km over 9 days and then intermittently swam and walked on the sea ice surface an additional 1,800 km. Measures of movement rate, hourly activity, and subcutaneous and external temperature revealed distinct profiles of swimming and walking. Between captures, this polar bear lost 22% of her body mass and her yearling cub. The extraordinary long distance swimming ability of polar bears, which we confirm here, may help them cope with reduced Arctic sea ice. Our observation, however, indicates that long distance swimming in Arctic waters, and travel over deep water pack ice, may result in high energetic costs and compromise reproductive fitness. ?? 2011 US Government.

  14. Wind-driven interannual variability of sea ice algal production over the western Arctic Chukchi Borderland

    Directory of Open Access Journals (Sweden)

    E. Watanabe

    2015-05-01

    Full Text Available Seasonal and interannual variability in sinking flux of biogenic particles was reported by the multi-year bottom-tethered sediment trap measurements in the Northwind Abyssal Plain (Station NAP: 75° N, 162° W, 1975 m water depth of the western Arctic Chukchi Borderland. Whereas the trapped particle flux had an obvious peak with the dominance of sea ice-related diatom valve in August 2011, the observed particle flux was considerably suppressed throughout the summer season in 2012. In the present study, response of ice algal production and biomass to wind-driven changes in physical environments was addressed using a pan-Arctic sea ice–ocean modeling approach. Sea ice ecosystem with ice algae was newly incorporated into the lower-trophic marine ecosystem model, which was previously coupled with a high-resolution (i.e., horizontal grid size of 5 km ocean general circulation model. Seasonal experiments covering two year-long mooring periods indicated that primary productivity of ice algae around the Chukchi Borderland depended on basin-scale wind pattern through various processes. Easterly wind in the southern part of distinct Beaufort High supplied high abundance of nutrient for euphotic zones of the NAP region via both surface Ekman transport of Chukchi shelf water and vertical turbulent mixing with underlying nutricline water as in 2011. In contrast, northwesterly wind flowing in the northern part of extended Siberian High transported oligotrophic water within the Beaufort Gyre circulation toward the NAP region as in 2012. The modeled ice algal biomass during the summer season certainly reflected the differences in nutrient distribution. The sinking flux of Particulate Organic Nitrogen (PON was comparable with the time series obtained from the sediment trap data in summer 2011. On the other hand, lateral advection of shelf-origin ice algal patch during a great cyclone event might have caused a model bias on the PON flux in 2012. The extension

  15. Dramatic variability of the carbonate system at a temperate coastal ocean site (Beaufort, North Carolina, USA is regulated by physical and biogeochemical processes on multiple timescales.

    Directory of Open Access Journals (Sweden)

    Zackary I Johnson

    Full Text Available Increasing atmospheric carbon dioxide (CO2 from anthropogenic sources is acidifying marine environments resulting in potentially dramatic consequences for the physical, chemical and biological functioning of these ecosystems. If current trends continue, mean ocean pH is expected to decrease by ~0.2 units over the next ~50 years. Yet, there is also substantial temporal variability in pH and other carbon system parameters in the ocean resulting in regions that already experience change that exceeds long-term projected trends in pH. This points to short-term dynamics as an important layer of complexity on top of long-term trends. Thus, in order to predict future climate change impacts, there is a critical need to characterize the natural range and dynamics of the marine carbonate system and the mechanisms responsible for observed variability. Here, we present pH and dissolved inorganic carbon (DIC at time intervals spanning 1 hour to >1 year from a dynamic, coastal, temperate marine system (Beaufort Inlet, Beaufort NC USA to characterize the carbonate system at multiple time scales. Daily and seasonal variation of the carbonate system is largely driven by temperature, alkalinity and the balance between primary production and respiration, but high frequency change (hours to days is further influenced by water mass movement (e.g. tides and stochastic events (e.g. storms. Both annual (~0.3 units and diurnal (~0.1 units variability in coastal ocean acidity are similar in magnitude to 50 year projections of ocean acidity associated with increasing atmospheric CO2. The environmental variables driving these changes highlight the importance of characterizing the complete carbonate system rather than just pH. Short-term dynamics of ocean carbon parameters may already exert significant pressure on some coastal marine ecosystems with implications for ecology, biogeochemistry and evolution and this shorter term variability layers additive effects and

  16. Melt ponds on Arctic sea ice determined from MODIS satellite data using an artificial neural network

    Directory of Open Access Journals (Sweden)

    A. Rösel

    2012-04-01

    Full Text Available Melt ponds on sea ice strongly reduce the surface albedo and accelerate the decay of Arctic sea ice. Due to different spectral properties of snow, ice, and water, the fractional coverage of these distinct surface types can be derived from multispectral sensors like the Moderate Resolution Image Spectroradiometer (MODIS using a spectral unmixing algorithm. The unmixing was implemented using a multilayer perceptron to reduce computational costs.

    Arctic-wide melt pond fractions and sea ice concentrations are derived from the level 3 MODIS surface reflectance product. The validation of the MODIS melt pond data set was conducted with aerial photos from the MELTEX campaign 2008 in the Beaufort Sea, data sets from the National Snow and Ice Data Center (NSIDC for 2000 and 2001 from four sites spread over the entire Arctic, and with ship observations from the trans-Arctic HOTRAX cruise in 2005. The root-mean-square errors range from 3.8 % for the comparison with HOTRAX data, over 10.7 % for the comparison with NSIDC data, to 10.3 % and 11.4 % for the comparison with MELTEX data, with coefficient of determination ranging from R2=0.28 to R2=0.45. The mean annual cycle of the melt pond fraction per grid cell for the entire Arctic shows a strong increase in June, reaching a maximum of 15 % by the end of June. The zonal mean of melt pond fractions indicates a dependence of the temporal development of melt ponds on the geographical latitude, and has its maximum in mid-July at latitudes between 80° and 88° N.

    Furthermore, the MODIS results are used to estimate the influence of melt ponds on retrievals of sea ice concentrations from passive microwave data. Results from a case study comparing sea ice concentrations from ARTIST Sea Ice-, NASA Team 2-, and Bootstrap-algorithms with MODIS sea ice concentrations indicate an underestimation of around 40 % for sea ice concentrations retrieved with microwave

  17. Measuring the point-spread function of sea ice in situ

    Science.gov (United States)

    Voss, Jeffrey M.; Honey, Richard C.; Gilbert, Gary D.; Buntzen, Rodney R.

    1992-12-01

    In this paper, we describe an experiment to measure the point spread function (PSF) of Arctic ice that was conducted by personnel of the Naval Ocean Systems Center in 1985. SRI International designed and developed the instrumentation. In April, data were collected on refrozen leads in pack ice concentrated near the Beaufort Gyre. The location was about 200 miles from the North Pole at approximately 86 degrees north and 88 degrees west. PSF measurements were made with a Hasselblad camera and a pulsed Lambertian (cosine) source gated to the camera. Recently, SRI digitized the film data with a charge-coupled device (CCD) camera and performed a digital analysis of the images. Results from two sites of new and first- year ice, 0.66 m and 2.1 m thick, respectively, are presented. Because of the strong multiple scattering by sea ice, and the limited area of the ice surface that could be imaged by the camera, the data obtained only partially characterize the PSF of the ice. The paper concludes with suggestions for improving future sea ice PSF measurements.

  18. Outflow of Pacific water from the Chukchi Sea to the Arctic Ocean

    Institute of Scientific and Technical Information of China (English)

    Robert S Pickart; Greg Stossmeister

    2008-01-01

    Pacific water exits the Chukchi Sea shelf through Barrow Canyon in the east and Herald Canyon in the west, forming an eastward-directed shelfbreak boundary current that flows into the Beaufort Sea. Here we summarize the transformation that the Pacific water undergoes in the two canyons, and describe the characteristics and variability of the resulting shelfbreak jet, using recently collected summertime hydrographic data and a year-long mooring data set. In both canyons the northward-flowing Pacific winter water switches from the western to the eastern flank of the canyon, interacting with the northward-flowing summer water. In Barrow canyon the vorticity structure of the current is altered, while in Herald canyon a new water mass mode is created. In both instances hydraulic effects are believed to be partly responsible for the observed changes. The shelfbreak jet that forms from the canyon outflows has distinct seasonal configurations, from a bottom-intensified flow carrying cold, dense Pacific water in spring, to a surface-intensified current advecting warm, buoyant water in summer. The current also varies significantly on short timescales, from less than a day to a week. In fall and winter much of this mesoscale variability is driven by storm events, whose easterly winds reverse the current and cause upwelling. Different types of eddies arc spawned from the current, which are characterized here using hydrographic and satellite data.

  19. Aral Sea basin: a sea dies, a sea also rises.

    Science.gov (United States)

    Glantz, Michael H

    2007-06-01

    The thesis of this article is quite different from many other theses of papers, books, and articles on the Aral Sea. It is meant to purposely highlight the reality of the situation in Central Asia: the Aral Sea that was once a thriving body of water is no more. That sea is dead. What does exist in its place are the Aral seas: there are in essence three bodies of water, one of which is being purposefully restored and its level is rising (the Little Aral), and two others which are still marginally connected, although they continue to decline in level (the Big Aral West and the Big Aral East). In 1960 the level of the sea was about 53 m above sea level. By 2006 the level had dropped by 23 m to 30 m above sea level. This was not a scenario generated by a computer model. It was a process of environmental degradation played out in real life in a matter of a few decades, primarily as a result of human activities. Despite wishes and words to the contrary, it will take a heroic global effort to save what remains of the Big Aral. It would also take a significant degree of sacrifice by people and governments in the region to restore the Big Aral to an acceptable level, given that the annual rate of flow reaching the Amudarya River delta is less than a 10th of what it was several decades ago. Conferring World Heritage status to the Aral Sea(s) could spark restoration efforts for the Big Aral. PMID:17626470

  20. Modeling of stability of gas hydrates under permafrost in an environment of surface climatic change – terrestrial case, Beaufort-Mackenzie basin, Canada

    Directory of Open Access Journals (Sweden)

    J. Majorowicz

    2011-09-01

    Full Text Available Modeling of the onset of permafrost formation and succeeding gas hydrate formation in the changing surface temperature environment has been done for the Beaufort-Mackenzie Basin (BMB. Numerical 1-D modeling is constrained by deep heat flow from deep well bottom hole temperatures, deep conductivity, present permafrost thickness and thickness of Type I gas hydrates. Latent heat effects were applied to the model for the entire ice bearing permafrost and Type I hydrate intervals. Modeling for a set of surface temperature forcing during the glacial-interglacial history including the last 14 Myr was performed. Two scenarios of gas formation were considered; case 1: formation of gas hydrate from gas entrapped under deep geological seals and case 2: formation of gas hydrate from gas in a free pore space simultaneously with permafrost formation. In case 1, gas hydrates could have formed at a depth of about 0.9 km only some 1 Myr ago. In case 2, the first gas hydrate formed in the depth range of 290–300 m shortly after 6 Myr ago when the GST dropped from −4.5 °C to −5.5. °C. The gas hydrate layer started to expand both downward and upward subsequently. These models show that the gas hydrate zone, while thinning persists under the thick body of BMB permafrost through the current interglacial warming periods.

  1. 7 CFR 1437.310 - Sea grass and sea oats.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Sea grass and sea oats. 1437.310 Section 1437.310 Agriculture Regulations of the Department of Agriculture (Continued) COMMODITY CREDIT CORPORATION, DEPARTMENT... Determining Coverage Using Value § 1437.310 Sea grass and sea oats. (a) Sea grass and sea oats are value...

  2. Sea Lion Diet Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — California sea lions pup and breed at four of the nine Channel Islands in southern California. Since 1981, SWFSC MMTD has been conducting a diet study of sea lions...

  3. Sea Turtle Interaction Report

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Sea Turtle Interaction Report is a report sent out in pdf format to authorized individuals that summarizes sea turtle interactions in the longline fishery. The...

  4. Decadal predictability of extreme fresh water export events from the Arctic Ocean into the Nordic Seas and subpolar North Atlantic

    Science.gov (United States)

    Schmith, Torben; Olsen, Steffen M.; Ringgaard, Ida M.; May, Wilhelm

    2016-04-01

    Abrupt fresh water releases originating in the Arctic Ocean have been documented to affect ocean circulation and climate in the North Atlantic area. Therefore, in this study, we investigate prospects for predicting such events up to one decade ahead. This is done in a perfect model setup by a combination of analyzing a 500 year control experiment and dedicated ensemble experiment aimed at predicting selected 10 year long segments of the control experiment. The selected segments are characterized by a large positive or negative trend in the total fresh water content in the Arctic Ocean. The analysis of the components (liquid fresh water and sea ice) reveals that they develop in a near random walk manner. From this we conclude that the main mechanism is integration of fresh water in the Beaufort Gyre through Ekman pumping from the randomly varying atmosphere. Therefore, the predictions from the ensemble experiments are on average not better than a damped persistence predictions. By running two different families of ensemble predictions, one starting from the 'observed' ocean globally, and one starting from climatology in the Arctic Ocean and from the observed ocean elsewhere, we conclude that the former outperforms the latter for the first few years as regards liquid fresh water and for the first year as regards sea ice. Analysis of the model experiments in terms of the fresh water export from the Arctic Ocean into Nordic seas and the subpolar North Atlantic reveals a very modest potential for predictability.

  5. Sea level rise

    OpenAIRE

    Warrick, R. A.; Oerlemans, J.

    1990-01-01

    This Section addresses three questions: Has global-mean sea level been rising during the last 100 years? What are the causal factors that could explain a past rise in sea level? And what increases in sea level can be expected in the future?

  6. Productivity, chlorophyll a, Photosynthetically Active Radiation (PAR) and other phytoplankton data from the Arctic Ocean, Bering Sea, Chukchi Sea, Beaufort Sea, East Siberian Sea, Kara Sea, Barents Sea, and Arctic Archipelago measured between 17 April, 1954 and 30 May, 2006 compiled as part of the Arctic System Science Primary Production (ARCSS-PP) observational synthesis project (NODC Accession 0063065)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Arctic Ocean primary production data were assembled from original input data archived in various international databases, provided by individual investigators or in...

  7. Synoptic measurements of subsurface phytoplankton layers collected from Fish Lidar, Oceanic, Experimenta (FLOE) Light Detection and Ranging (LIDAR) from aircraft in Chukchi Sea and Beaufort Sea from 2014-07-17 to 2014-07-29 (NCEI Accession 0128217)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In July 2014, FLOE was installed in a NOAA Twin Otter to make the first synoptic measurements of subsurface phytoplankton layers associated with the retreating ice...

  8. Underway meteorological, navigational, physical and time series data collected aboard the NOAA Ship Rainier in the Beaufort Sea, Bering Sea and others from 2015-06-19 to 2015-08-27 (NCEI Accession 0130918)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0130918 contains raw underway meteorological, navigational, physical and time series data logged by the Scientific Computer System (SCS) aboard the...

  9. Spatial and temporal multiyear sea ice distributions in the Arctic: A neural network analysis of SSM/I data, 1988?2001

    Science.gov (United States)

    Belchansky, G.I.; Douglas, D.C.; Alpatsky, I.V.; Platonov, N.G.

    2004-01-01

    Arctic multiyear sea ice concentration maps for January 1988-2001 were generated from SSM/I brightness temperatures (19H, 19V, and 37V) using modified multiple layer perceptron neural networks. Learning data for the neural networks were extracted from ice maps derived from Okean and ERS satellite imagery to capitalize on the stability of active radar multiyear ice signatures. Evaluations of three learning algorithms and several topologies indicated that networks constructed with error back propagation learning and 3-20-1 topology produced the most consistent and physically plausible results. Operational neural networks were developed specifically with January learning data, and then used to estimate daily multiyear ice concentrations from daily-averaged SSM/I brightness temperatures during January. Monthly mean maps were produced for analysis by averaging the respective daily estimates. The 14-year series of January multiyear ice distributions revealed dense and persistent cover in the central Arctic surrounded by expansive regions of highly fluctuating interannual cover. Estimates of total multiyear ice area by the neural network were intermediate to those of other passive microwave algorithms, but annual fluctuations and trends were similar among all algorithms. When compared to Radarsat estimates of multiyear ice concentration in the Beaufort and Chukchi Seas (1997-1999), average discrepancies were small (0.9-2.5%) and spatial coherency was reasonable, indicating the neural network's Okean and ERS learning data facilitated passive microwave inversion that emulated backscatter signatures. During 1988-2001, total January multiyear ice area declined at a significant linear rate of -54.3 x 10^3 km2/yr (-1.4%/yr). The most persistent and extensive decline in multiyear ice concentration (-3.3%/yr) occurred in the southern Beaufort and Chukchi Seas. In autumn 1996, a large multiyear ice recruitment of over 106 km2 (mostly in the Siberian Arctic) fully replenished the

  10. Circumpolar Arctic greening: Relationships to summer sea-ice concentrations, land temperatures and disturbance regimes

    Science.gov (United States)

    Walker, D. A.; Bhatt, U. S.; Epstein, H. E.; Raynolds, M. K.; Frost, G. V.; Leibman, M. O.; Khomutov, A.; Jia, G.; Comiso, J. C.; Pinzon, J. E.; Tucker, C. J.; Webber, P. J.; Tweedie, C. E.

    2009-12-01

    The global distribution of Arctic tundra vegetation is closely tied to the presence of summer sea ice. Models predict that the reduction of sea ice will cause large changes to summer land-surface temperatures. Warming combined with increased natural and anthropogenic disturbance are expected to greatly increase arctic tundra productivity. To examine where tundra productivity is changing most rapidly, we studied 1982-2008 trends of sea-ice concentrations, summer warmth index (SWI) and the annual Maximum Normalized Difference Vegetation Index (MaxNDVI). We summarize the results according to the tundra adjacent to 14 Arctic seas. Sea-ice concentrations have declined and summer land temperatures have increased in all parts of the Arctic coast. The overall percentage increase in Arctic MaxNDVI was +7%. The trend was much greater in North America (+11%) than in Eurasia (+4%). Large percentage increases of MaxNDVI occurred inland from Davis Straight (+20%), Baffin Bay (+18%), Canadian Archipelago (+14%), Beaufort Sea (+12%), and Laptev Sea (+8%). Declines occurred in the W. Chukchi (-6%) and E. Bering (-5%) seas. The changes in NDVI are strongly correlated to changes in summer ground temperatures. Two examples from a 900-km north-south Arctic transect in Russia and long-term observations at a High Arctic site in Canada provide insights to where the changes in productivity are occurring most rapidly. At tree line near Kharp in northwest Siberia, alder shrubs are expanding vigorously in fire-disturbed areas; seedling establishment is occurring primarily in areas with disturbed mineral soils, particularly nonsorted circles. In the Low Arctic tundra areas of the central Yamal Peninsula greening is concentrated in riparian areas and upland landslides associated with degrading massive ground ice, where low-willow shrublands replace the zonal sedge, dwarf-shrub tundra growing on nutrient-poor sands. In polar desert landscapes near the Barnes Ice Cap, Baffin Island, Canada

  11. Waves in the seas

    Digital Repository Service at National Institute of Oceanography (India)

    Varkey, M.J.

    of wave-energy for generation of electricty. Wind while blowing over the sea surface trans- fers huge amounts of energy into the sea by imparting oscillatory motion to the surface. This includes both ki- netic and potential Chaotic sea surface; (inset) a... stimulation and excite- ment since it has much complexity and scope for further developments. The recently developed wonder-tool of mathematics, 'fractals' can also be used to model sea surfaces. Generation of waves on the sea surface is a very complex process...

  12. Sea level report

    International Nuclear Information System (INIS)

    Study of Cenozoic Era sea levels shows a continual lowering of sea level through the Tertiary Period. This overall drop in sea level accompanied the Pleistocene Epoch glacio-eustatic fluctuations. The considerable change of Pleistocene Epoch sea level is most directly attributable to the glacio-eustatic factor, with a time span of 105 years and an amplitude or range of approximately 200 m. The lowering of sea level since the end of the Cretaceous Period is attributed to subsidence and mid-ocean ridges. The maximum rate for sea level change is 4 cm/y. At present, mean sea level is rising at about 3 to 4 mm/y. Glacio-eustacy and tectono-eustacy are the parameters for predicting sea level changes in the next 1 my. Glacio-eustatic sea level changes may be projected on the basis of the Milankovitch Theory. Predictions about tectono-eustatic sea level changes, however, involve predictions about future tectonic activity and are therefore somewhat difficult to make. Coastal erosion and sedimentation are affected by changes in sea level. Erosion rates for soft sediments may be as much as 50 m/y. The maximum sedimentation accumulation rate is 20 m/100 y

  13. Sea level extremes in the Caribbean Sea

    OpenAIRE

    Torres, R. Ricardo; Tsimplis, Michael N.

    2014-01-01

    Sea level extremes in the Caribbean Sea are analyzed on the basis of hourly records from 13 tide gauges. The largest sea level extreme observed is 83 cm at Port Spain. The largest nontidal residual in the records is 76 cm, forced by a category 5 hurricane. Storm surges in the Caribbean are primarily caused by tropical storms and stationary cold fronts intruding the basin. However, the seasonal signal and mesoscale eddies also contribute to the creation of extremes. The five stations that have...

  14. Sea piracy and law of the sea

    OpenAIRE

    Hanif, Muhammad Tahir

    2010-01-01

    As the sea become world’s largest source to trade between the nations during the last few decades. Of course there are lots of problems in this regards when we are using the sea on such a large scale. The problem of piracy is most dangerous problems, among the all problems of the sea at the same time. Nations are trying to control this crime individually and collectively but the problem is still on its peak. Lots of international and national laws and conventions are held in this ...

  15. Salish Sea Genetics - Salish Sea genetic inventory

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Salish Sea comprises most of the Puget Sound water area. Marine species are generally assemblages of discrete populations occupying various ecological niches....

  16. Summer Arctic sea fog

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Synchronous or quasi-synchronous sea-land-air observations were conducted using advanced sea ice, atmospheric and marine instruments during China' s First Arctic Expedition. Based on the Precious data from the expedition, it was found that in the Arctic Ocean, most part of which is covered with ice or is mixed with ice, various kinds of sea fog formed such as advection fog, radiation fog and vapor fog. Each kind has its own characteristic and mechanics of creation. In the southern part of the Arctic Ocean, due to the sufficient warm and wet flow there, it is favorable for advection fog to form,which is dense and lasts a long time. On ice cap or vast floating ice, due to the strong radiation cooling effect, stable radiating fog is likely to form. In floating ice area there forms vapor fog with the appearance of masses of vapor from a boiling pot, which is different from short-lasting land fog. The study indicates that the reason why there are many kinds of sea fog form in the Arctic Ocean is because of the complicated cushion and the consequent sea-air interaction caused by the sea ice distribution and its unique physical characteristics. Sea fog is the atmospheric phenomenon of sea-air heat exchange. Especially, due to the high albedo of ice and snow surface, it is diffcult to absorb great amount of solar radiation during the polar days. Besides, ice is a poor conductor of heat; it blocks the sea-air heat exchange.The sea-air exchange is active in floating ice area where the ice is broken. The sea sends heat to the atmosphere in form of latent heat; vapor fog is a way of sea-air heat exchange influencing the climate and an indicator of the extent of the exchange. The study also indicates that the sea also transports heat to the atmosphere in form of sensible heat when vapor fog occurs.

  17. 加拿大Beaufort-Mackenzie盆地通过区域温度场变化探测到的油气运移

    Institute of Scientific and Technical Information of China (English)

    Kirk G.Osadetz; 金晶(译)

    2009-01-01

    Beaufort-Mackenzie盆地中途测试和井底温度录井资料所反映出的区域温度场的特征表明,西Beaufort海和断裂带沿线两处的热异常都与特定的地质背景有关。在西Beaufort海,始新世后的侵蚀作用削蚀了新生代的地层,而压实环境中的褶皱现象也较常见;在断裂带沿线,上升流通过平流传递热。在始新世和始新世后快速沉降的沉积中心、3000m(9843ft)以下已开发的超压地层则温度下降。沿裂谷边缘东南部的较老地层以正常地温为特征。平面图和横剖面图中异常高温的现象,说明断裂带和较大规模的区域含水层调节了来自深部超压层的流体的向上排替。在有许多大的油气新发现的区域都可见到异常高温,说明油气是沿着相同的通道运移的。因此,识别温度场异常可能是一种非常有效的勘探方法。

  18. A Possible Feedback Mechanism Involving the Arctic Freshwater,the Arctic Sea Ice, and the North Atlantic Drift

    Institute of Scientific and Technical Information of China (English)

    Odd Helge OTTER(A); Helge DRANGE

    2004-01-01

    Model studies point to enhanced warming and to increased freshwater fluxes to high northern latitudes in response to global warming. In order to address possible feedbacks in the ice-ocean system in response to such changes, the combined effect of increased freshwater input to the Arctic Ocean and Arctic warming--the latter manifested as a gradual melting of the Arctic sea ice--is examined using a 3-D isopycnic coordinate ocean general circulation model. A suite of three idealized experiments is carried out: one control integration, one integration with a doubling of the modern Arctic river runoff, and a third more extreme case, where the river runoff is five times the modern value. In the two freshwater cases, the sea ice thickness is reduced by 1.5-2 m in the central Arctic Ocean over a 50-year period. The modelled ocean response is qualitatively the same for both perturbation experiments: freshwater propagates into the Atlantic Ocean and the Nordic Seas, leading to an initial weakening of the North Atlantic Drift.Furthermore, changes in the geostrophic currents in the central Arctic and melting of the Arctic sea ice lead to an intensified Beaufort Gyre, which in turn increases the southward volume transport through the Canadian Archipelago. To compensate for this southward transport of mass, more warm and saline Atlantic water is carried northward with the North Atlantic Drift. It is found that the increased transport of salt into the northern North Atlantic and the Nordic Seas tends to counteract the impact of the increased freshwater originating from the Arctic, leading to a stabilization of the North Atlantic Drift.

  19. South China Sea Challenge

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    China's attempts to solve disputes with ASEAN over the South China Sea help regional peace China's marine economy and security are currently faced with new challenges, requiring careful handling, especially in disputes with ASEAN countries and in promoting common development of the South China Sea. The outcome of how this is dealt with could undoubtedly pave the way for solutions to other oceanic disputes. The South China Sea is located south of

  20. Microwave emission from high Arctic Sea ice during freeze-up

    Science.gov (United States)

    Hollinger, J. P.; Troy, B. E.; Ramseier, R. O.; Asmus, K. W.; Hartman, M. F.; Luther, C. A.

    1984-09-01

    A cooperative sea ice remote sensing experiment was conducted in the eastern Beaufort Sea and Mould Bay area during the freeze-up period in October 1981. Airborne millimeter-wave imagery at 90, 140, and 220 GHz, and nadir microwave radiometric measurements at 19, 22, and 31 GHz, were made from a U. S. Naval Research Laboratory aircraft, while the Canadian Atmospheric Environment Service conducted an extensive concurrent surface measurement program. This study demonstrates for the first time the high-resolution capability of 90 GHz to investigate detailed ice morphology and to define ice types. The 140 and 220 GHz imagery is the first ever made of sea ice at these high frequencies. Emissivities are determined for young ice, second-year ice (SY), multiyear ice (MY), new ice, old shorefast ice, and open water. The young ice exhibits the emissivity typical of first-year (FY) ice types, i.e., near unity and independent of frequency. The emissivities of new ice and open water increase with frequency, and that of MY ice decreases with frequency. Those of SY ice and old shorefast ice, measured here for the first time, also decrease with frequency but are larger in value than the MY emissivity. Ice type discrimination is optimum at 90 GHz, i.e., the spread in microwave signature between FY ice and old ice (SY and MY) is greatest at 90 GHz. The MY emissivity is lower than that of open water at both 90 and 140 GHz. The measurements presented here provide a basis for development of algorithms to exploit the potential of the Mission Sensor Microwave/Imager (SSM/I) to be launched on a Defense Meteorological Satellite in 1985 and, in particular, the 85.5-GHz SSM/I channels for ice type, concentration, and edge determination.

  1. Lead detection in Arctic sea ice from CryoSat-2: quality assessment, lead area fraction and width distribution

    Directory of Open Access Journals (Sweden)

    A. Wernecke

    2015-03-01

    Full Text Available Leads cover only a small fraction of the Arctic sea ice but they have a dominant effect on the turbulent exchange between the ocean and the atmosphere. A supervised classification of CryoSat-2 measurements is performed by a combination with visual MODIS scenes. For several parameters thresholds are optimized and tested in order to reproduce this prior classification. The maximum power of the waveform shows the best classification properties amongst them, including the Pulse Peakiness. With the same correct lead detection rates as of published classifiers, the amount of ice being detected as lead can be reduced by up to 40%. Lead area fraction estimates based on CryoSat-2 show a major fracturing event in the Beaufort Sea in 2013. The resulting Arctic wide lead width distribution follows a power law with an exponent of 2.47 ± 0.04 for the winter seasons from 2011 to 2014, confirming and complementing a regional study based on a high resolution SPOT image.

  2. Sea surface temperatures and salinities from platforms in the Barents Sea, Sea of Japan, North Atlantic Ocean, Philippine Sea, Red Sea, and the South China Sea (Nan Hai) from 1896-1950 (NODC Accession 0000506)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Surface temperatures and salinities were collected in the Barents Sea, Sea of Japan, North Atlantic Ocean, Philippine Sea, Red Sea, and South China Sea (Nan Hai)...

  3. Oceanography of marginal seas

    Digital Repository Service at National Institute of Oceanography (India)

    DileepKumar, M.

    . The Andaman Sea remains the least studied basin in this region. Physical and chemical signatures suggest that the deep basin of the Andaman Sea are largely influenced by intermediate circulation. Deep waters are warmer and low in oxygen than those at similar...

  4. SEA and planning

    DEFF Research Database (Denmark)

    Stoeglehner, G.; Brown, A.L.; Kørnøv, Lone

    2009-01-01

    relationship of the SEA to the planning activity itself. This paper focuses on the influence that planners have in these implementation processes, postulating the hypothesis that these are key players in achieving effectiveness in SEA. Based upon implementation theory and empirical experience, the paper...

  5. Dilemmas in SEA application

    DEFF Research Database (Denmark)

    Lyhne, Ivar

    Dilemmas in SEA Application: The DK Energy SectorIvar Lyhne - lyhne@plan.aau.dk. Based on three years of collaborative research, this paper outlines dilemmas in the application of SEA in the strategic development of the Danish energy sector. The dilemmas are based on concrete examples from practice...

  6. Motorways of the Sea

    OpenAIRE

    Ionita Profir

    2011-01-01

    In its communication aim, the European Commission presents the following definition: short distance shipping means the movement of cargo and passengers by sea between ports situated in Europe geographical area or between those ports and ports situated in non-European countries located at closed seas on the border of Europe

  7. North Sea update

    International Nuclear Information System (INIS)

    The article deals with the offshore activity in the North Sea bringing together a special update feature for the petroleum industries in the United Kingdom, Norway, Denmark and the Netherlands. The total capital expenditure required for the period from 1995 to 1998 for the North Sea area which includes exploration, development projects and well abandoning, are discussed and presented. 20 figs., 5 tabs

  8. IOMASA SEA ICE DEVELOPMENTS

    DEFF Research Database (Denmark)

    Andersen, Søren; Tonboe, Rasmus; Heygster, Georg; Melsheimer, Christian; Pedersen, Leif Toudal; Schyberg, Harald; Tveter, Frank; Dahlgren, Per; Lundelius, Tomas; Gustafsson, Nils

    2005-01-01

    Sensitivity studies show that the radiometer ice concentration estimate can be biased by +10% by anomalous atmospheric emissivity and -20% by anomalous ice surface emissivity. The aim of the sea ice activities in EU 5th FP project IOMASA is to improve sea ice concentration estimates at higher...... spatial resolution. The project is in the process of facilitating an ice concentration observing system through validation and a better understanding of the microwave radiative transfer of the sea ice and overlying snow layers. By use of a novel modelling approach, it is possible to better detect and...... determine the circumstances that may lead to anomalous sea ice concentration retrieval as well as to assess and possibly minimize the sensitivities of the retrieval system. Through an active partnership with the SAF on Ocean and Sea Ice, a prototype system will be implemented as an experimental product...

  9. Field and Satellite Observations of the Formation and Distribution of Arctic Atmospheric Bromine Above a Rejuvenated Sea Ice Cover

    Science.gov (United States)

    Nghiem, Son V.; Rigor, Ignatius G.; Richter, Andreas; Burrows, John P.; Shepson, Paul B.; Bottenheim, Jan; Barber, David G.; Steffen, Alexandra; Latonas, Jeff; Wang, Feiyue; Stern, Gary; Clemente-Colon, Pablo; Martin, Seelye; Hall, Dorothy K.; Kaleschke, Lars; Tackett, Philip; Neumann, Gregory; Asplin, Matthew G.

    2012-01-01

    Recent drastic reduction of the older perennial sea ice in the Arctic Ocean has resulted in a vast expansion of younger and saltier seasonal sea ice. This increase in the salinity of the overall ice cover could impact tropospheric chemical processes. Springtime perennial ice extent in 2008 and 2009 broke the half-century record minimum in 2007 by about one million km2. In both years seasonal ice was dominant across the Beaufort Sea extending to the Amundsen Gulf, where significant field and satellite observations of sea ice, temperature, and atmospheric chemicals have been made. Measurements at the site of the Canadian Coast Guard Ship Amundsen ice breaker in the Amundsen Gulf showed events of increased bromine monoxide (BrO), coupled with decreases of ozone (O3) and gaseous elemental mercury (GEM), during cold periods in March 2008. The timing of the main event of BrO, O3, and GEM changes was found to be consistent with BrO observed by satellites over an extensive area around the site. Furthermore, satellite sensors detected a doubling of atmospheric BrO in a vortex associated with a spiral rising air pattern. In spring 2009, excessive and widespread bromine explosions occurred in the same region while the regional air temperature was low and the extent of perennial ice was significantly reduced compared to the case in 2008. Using satellite observations together with a Rising-Air-Parcel model, we discover a topographic control on BrO distribution such that the Alaskan North Slope and the Canadian Shield region were exposed to elevated BrO, whereas the surrounding mountains isolated the Alaskan interior from bromine intrusion.

  10. Impact of Arctic sea-ice retreat on the recent change in cloud-base height during autumn

    Science.gov (United States)

    Sato, K.; Inoue, J.; Kodama, Y.; Overland, J. E.

    2012-12-01

    Cloud-base observations over the ice-free Chukchi and Beaufort Seas in autumn were conducted using a shipboard ceilometer and radiosondes during the 1999-2010 cruises of the Japanese R/V Mirai. To understand the recent change in cloud base height over the Arctic Ocean, these cloud-base height data were compared with the observation data under ice-covered situation during SHEBA (the Surface Heat Budget of the Arctic Ocean project in 1998). Our ice-free results showed a 30 % decrease (increase) in the frequency of low clouds with a ceiling below (above) 500 m. Temperature profiles revealed that the boundary layer was well developed over the ice-free ocean in the 2000s, whereas a stable layer dominated during the ice-covered period in 1998. The change in surface boundary conditions likely resulted in the difference in cloud-base height, although it had little impact on air temperatures in the mid- and upper troposphere. Data from the 2010 R/V Mirai cruise were investigated in detail in terms of air-sea temperature difference. This suggests that stratus cloud over the sea ice has been replaced as stratocumulus clouds with low cloud fraction due to the decrease in static stability induced by the sea-ice retreat. The relationship between cloud-base height and air-sea temperature difference (SST-Ts) was analyzed in detail using special section data during 2010 cruise data. Stratus clouds near the sea surface were predominant under a warm advection situation, whereas stratocumulus clouds with a cloud-free layer were significant under a cold advection situation. The threshold temperature difference between sea surface and air temperatures for distinguishing the dominant cloud types was 3 K. Anomalous upward turbulent heat fluxes associated with the sea-ice retreat have likely contributed to warming of the lower troposphere. Frequency distribution of the cloud-base height (km) detected by a ceilometer/lidar (black bars) and radiosondes (gray bars), and profiles of potential

  11. Intermittent Sea Level Acceleration

    OpenAIRE

    Olivieri, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Spada, G.; Dipartimento di Scienze di Base e Fondamenti, Università di Urbino Carlo Bo, Urbino

    2013-01-01

    Using instrumental observations from the Permanent Service for Mean Sea Level (PSMSL), we provide a new assessment of the global sea{level acceleration for the last 2 centuries (1820-2010). Our results, obtained by a stack of tide gauge time series, con firm the existence of a global sea level acceleration (GSLA) and, coherently with independent assessments so far, they point to a value close to 0:01 mm/yr2. However, di fferently from previous studies, we discuss how change points or ...

  12. Changes in Sea Level

    OpenAIRE

    Church, J.A.; Gregory, J. M.; Huybrechts, Philippe; Kuhn, M.; Lambeck, K.; Nhuan, M. T.; Qin, D.; Woodworth, P. L.

    2001-01-01

    This chapter assesses the current state of knowledge of the rate of change of global-averaged and regional sea-level in relation to climate change. We focus on the 20th and 21st centuries.However, because of the slow response to past conditions of the oceans and ice sheets and the consequent land movements, we consider changes in sea level prior to the historical record, andwe also look over a thousand years into the future.Past changes in sea levelFrom recent analyses, our conclusions are as...

  13. Caspian sea: petroleum challenges

    International Nuclear Information System (INIS)

    The Caspian sea is one of the world areas the most promising in terms of investments and petroleum development. This study presents the petroleum challenges generated by this hydrocarbons reserve. The first part discusses the juridical status (sea or lake), the petroleum and the gas reserves, the ecosystem and the today environment (fishing and caviar), the geostrategic situation and the transport of gas and oil. It provides also a chronology from 1729 to 2005, a selection of Internet sites, books and reports on the subject and identity sheets of the countries around the Caspian sea. (A.L.B.)

  14. Sea Scallop Survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The standardized NEFSC Sea Scallop Survey began in 1980 and has covered an area from Cape Hatteras to Georges Bank. The survey aims to determine the distribution...

  15. Baltic Sea: Radionuclides

    DEFF Research Database (Denmark)

    Nielsen, Sven Poul; Lüning, Maria; Ilus, Erkki;

    2011-01-01

    The most significant source of anthropogenic radioactivity in the Baltic Sea is fallout from the accident at the Chernobyl nuclear power plant in 1986. The second most important source is global fallout from atmospheric nuclear weapons tests carried out during the late 1950s and early 1960s....... Radioactivity inputs into the Baltic Sea from nuclear reprocessing plants in Western Europe have become of minor importance due to significant reduction of discharges in recent years. In terms of input of 137Cs into the Baltic Sea, Chernobyl fallout has contributed about 82% and nuclear weapons test fallout...... about 14%. For 90Sr in the Baltic Sea, input from atmospheric fallout from nuclear weapons tests has contributed about 81%, while the contribution from Chernobyl fallout was about 13%. Cesium-137 is the main indicator of Baltic seawater with respect to anthropogenic radioactivity. The highest...

  16. South China Sea

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Chinese Foreign Minister Yang Jiechi warned against attempts to "in-ternationalize" the issue of the South China Sea, where China has territorial disputes with some ASEAN member states, including Viet Nam and the

  17. Black Sea aerosols

    International Nuclear Information System (INIS)

    Shipboard, high volume air particulate samples were collected from the Black Sea atmosphere and analyzed by instrumental neutron activation analysis, atomic absorption spectrophotometry and ion chromatography for about 40 elements and ions. Concentrations of elements in the eastern and western parts of the Black Sea are different at the 95% confidence level, with lower concentrations in the eastern Black Sea. Back-trajectories and concentrations of elements in trajectory groups show that Europe accounts for more than 70% of the anthropogenic elements in the atmosphere. The average sulfate concentration was 7 μg/m3, which is comparable with rural sulfate levels in western Europe. Fluxes of elements from the atmosphere to the Black Sea are in good agreement with the results of similar flux calculations for other regions

  18. Mediterranean sea level variations.

    Science.gov (United States)

    Vigo, I.; Sánchez Reales, J. M.; García, D.; Chao, B. F.

    2009-04-01

    In this work we report an updated study of the sea level variations for the Mediterranean sea for the period from October 1992 to January 2008. The study addresses two mayor issues: (i)The analysis of the spatial and temporal variability of sea surface height (SSH) from radar altimetry measurements (from TOPEX/Poseidon (T/P) + Jason-1, etc.). We use EOF analysis to explain most of its interannual variation, and how the different basins interact. (ii) The analysis of dynamics and balance of water mass transport for the whole period. We estimate the steric SSH by combining the steric SSH estimated from temperature and salt profiles simulated by the ECCO model with time-variable gravity (TVG) data (from GRACE) for the Mediterranean Sea. The estimated steric SSH together with the SSH obtained from altimetry allow for a more realistic estimation of the water mass variations in the Mediterranean for the whole period.

  19. ROE Sea Level Relative

    Data.gov (United States)

    U.S. Environmental Protection Agency — This point dataset represents changes in relative sea level along U.S. coasts, 1960-2013. Data were provided by the National Oceanic and Atmospheric Administration...

  20. Pollution of coastal seas

    Digital Repository Service at National Institute of Oceanography (India)

    Varkey, M.J.

    cities. Various types of wastes, if not properly treated, would cause serious pollution of these shallow seas endangering marine life and spoiling recreational facilities. Different polluting agents like sewage, chemicals, industrial coolants etc...

  1. South China Sea

    Energy Technology Data Exchange (ETDEWEB)

    Morton, Brian [Hong Kong Univ., Swire Inst. of Marine Science, Hong Kong (China); Hong Kong Univ., Dept. of Ecology and Biodiversity, Hong Kong (China); Blackmore, Graham [Hong Kong Univ. of Science and Technology, Dept. of Biology, Hong Kong (China)

    2001-07-01

    The South China Sea is poorly understood in terms of its marine biota, ecology and the human impacts upon it. What is known is most often contained in reports and workshops and conference documents that are not available to the wider scientific community. The South China Sea has an area of some 3.3 million km{sup 2} and depths range from the shallowest coastal fringe to 5377m in the Manila Trench. It is also studded with numerous islets, atolls and reefs many of which are just awash at low tide. It is largely confined within the Tropic of Cancer and, therefore, experiences a monsoonal climate being influenced by the Southwest Monsoon in summer and the Northeast Monsoon in winter. The South China Sea is a marginal sea and, therefore, largely surrounded by land. Countries that have a major influence on and claims to the sea include China, Malaysia, the Philippines and Vietnam, although Thailand, Indonesia and Taiwan have some too. The coastal fringes of the South China Sea are home to about 270 million people that have had some of the fastest developing and most vibrant economics on the globe. Consequently, anthropogenic impacts, such as over-exploitation of resources and pollution, are anticipated to be huge although, in reality, relatively little is known about them. The Indo-West Pacific biogeographic province, at the centre of which the South China Sea lies, is probably the world's most diverse shallow-water marine area. Of three major nearshore habitat types, i.e., coral reefs, mangroves and seagrasses, 45 mangrove species out of a global total of 51, most of the currently recognised 70 coral genera and 20 of 50 known seagrass species have been recorded from the South China Sea. The island groups of the South China Sea are all disputed and sovereignty is claimed over them by a number of countries. Conflicts have in recent decades arisen over them because of perceived national rights. It is perhaps because of this that so little research has been undertaken

  2. Understanding sea level changes

    OpenAIRE

    Chao, BF; Farr, T.; Labrecque, J; Bindschadler, R.; Douglas, B; E. Rignot; Shum, CK; Wahr, J.

    2002-01-01

    Sea level change occurs on all timescales, depending on the type of change in question. It also occurs with a continuous range of spatial scales-local, regional, and global. To understand and be able to eventually predict sea level changes is a truly interdisciplinary endeavor. It requires geodetic and non-geodetic measurements of various types from space as well as in situ, while various numerical models for a number of meteorological and geophysical processes or properties are essential or ...

  3. Canterbury Basin Sea Level

    OpenAIRE

    Fulthorpe, C. S.; Institute for Geophysics John A. and Katherine G. Jackson School of Geosciences The University of Texas at Austin J.J. Pickle Research Campus, Building 196 (ROC) 10100 Burnet Road (R2200) Austin TX 78758-4445 USA; Hoyanagi, K.; Department of Geology Faculty of Science Shinshu University 3-1-1 Asahi, Matsumoto 390-8621 Japan; Blum, P.; United States Implementing Organization Integrated Ocean Drilling Program Texas A&M University 1000 Discovery Drive College Station TX 77845 USA; Guèrin, G.; Borehole Research Group Lamont-Doherty Earth Observatory of Columbia University PO Box 1000, 61 Route 9W Palisades NY 10964 USA; Slagle, A. L.; Borehole Research Group Lamont-Doherty Earth Observatory of Columbia University PO Box 1000, 61 Route 9W Palisades NY 10964 USA; Blair, S. A.; Department of Geological Sciences Florida State University 006 Carraway Building Tallahassee FL 32306 USA; Browne, G. H.; Hydrocarbon Section GNS Science PO Box 30368 Lower Hutt New Zealand; Carter, R. M.; Marine Geophysical Laboratory James Cook University of North Queensland Townsville QLD 4811 Australia; Ciobanu, M.; Laboratoire de Microbiologie des Environnements Extrêmes CNRS UMR-6197 Institut Universitaire Européen de la Mer Technopole Brest-Iroise Plouzane 29280 France; Claypool, G. E.; Organic Geochemist 8910 West 2nd Avenue Lakewood CO 80226 USA; Crundwell, M. P.; New Zealand Observer/Paleontologist (foraminifers) Paleontology and Environmental Change Section GNS Science PO Box 30368 Lower Hutt New Zealand; Dinarès-Turell, J.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Ding, X.; School of Marine Sciences China University of Geosciences (Beijing) 29 XueYuan Road, Haidian District Beijing P.R. China; George, S. C.; Department of Earth and Planetary Sciences Macquarie University Sydney NSW 2109 Australia; Hepp, D. A.; MARUM – Center for Marine Environmental Sciences and Department of Geosciences University of Bremen Leobener Strasse MARUM Building, Room 2230 28359 Bremen Germany

    2010-01-01

    Integrated Ocean Drilling Program (IODP) Expedition 317 was devoted to understanding the relative importance of global sea level (eustasy) versus local tectonic and sedimentary processes in controlling continental margin sedimentary cycles. The expedition recovered sediments from the Eocene to recent period, with a particular focus on the sequence stratigraphy of the late Miocene to recent, when global sea level change was dominated by glacioeustasy. Drilling in the Canterbury Basin,...

  4. Affects of Changes in Sea Ice Cover on Bowhead Whales and Subsistence Whaling in the Western Arctic

    Science.gov (United States)

    Moore, S.; Suydam, R.; Overland, J.; Laidre, K.; George, J.; Demaster, D.

    2004-12-01

    Global warming may disproportionately affect Arctic marine mammals and disrupt traditional subsistence hunting activities. Based upon analyses of a 24-year time series (1979-2002) of satellite-derived sea ice cover, we identified significant positive trends in the amount of open-water in three large and five small-scale regions in the western Arctic, including habitats where bowhead whales (Balaena mysticetus) feed or are suspected to feed. Bowheads are the only mysticete whale endemic to the Arctic and a cultural keystone species for Native peoples from northwestern Alaska and Chukotka, Russia. While copepods (Calanus spp.) are a mainstay of the bowhead diet, prey sampling conducted in the offshore region of northern Chukotka and stomach contents from whales harvested offshore of the northern Alaskan coast indicate that euphausiids (Thysanoessa spp.) advected from the Bering Sea are also common prey in autumn. Early departure of sea ice has been posited to control availability of zooplankton in the southeastern Bering Sea and in the Cape Bathurst polynya in the southeastern Canadian Beaufort Sea, with maximum secondary production associated with a late phytoplankton bloom in insolatoin-stratified open water. While it is unclear if declining sea-ice has directly affected production or advection of bowhead prey, an extension of the open-water season increases opportunities for Native subsistence whaling in autumn. Therefore, bowhead whales may provide a nexus for simultaneous exploration of the effects sea ice reduction on pagophillic marine mammals and on the social systems of the subsistence hunting community in the western Arctic. The NOAA/Alaska Fisheries Science Center and NSB/Department of Wildlife Management will investigate bowhead whale stock identity, seasonal distribution and subsistence use patterns during the International Polar Year, as an extension of research planned for 2005-06. This research is in response to recommendations from the Scientific

  5. The Dead Sea

    Science.gov (United States)

    2006-01-01

    The Dead Sea is the lowest point on Earth at 418 meters below sea level, and also one of the saltiest bodies of water on Earth with a salinity of about 300 parts-per-thousand (nine times greater than ocean salinity). It is located on the border between Jordan and Israel, and is fed by the Jordan River. The Dead Sea is located in the Dead Sea Rift, formed as a result of the Arabian tectonic plate moving northward away from the African Plate. The mineral content of the Dead Sea is significantly different from that of ocean water, consisting of approximately 53% magnesium chloride, 37% potassium chloride and 8% sodium chloride. In the early part of the 20th century, the Dead Sea began to attract interest from chemists who deduced that the Sea was a natural deposit of potash and bromine. From the Dead Sea brine, Israel and Jordan produce 3.8 million tons potash, 200,000 tons elemental bromine, 45,000 tons caustic soda, 25, 000 tons magnesium metal, and sodium chloride. Both countries use extensive salt evaporation pans that have essentially diked the entire southern end of the Dead Sea. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet. ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining

  6. A Comparison of Snow Depth on Sea Ice Retrievals Using Airborne Altimeters and an AMSR-E Simulator

    Science.gov (United States)

    Cavalieri, D. J.; Marksu, T.; Ivanoff, A.; Miller, J. A.; Brucker, L.; Sturm, M.; Maslanik, J. A.; Heinrichs, J. F.; Gasiewski, A.; Leuschen, C.; Krabill, W.; Sonntag, J.

    2011-01-01

    A comparison of snow depths on sea ice was made using airborne altimeters and an Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) simulator. The data were collected during the March 2006 National Aeronautics and Space Administration (NASA) Arctic field campaign utilizing the NASA P-3B aircraft. The campaign consisted of an initial series of coordinated surface and aircraft measurements over Elson Lagoon, Alaska and adjacent seas followed by a series of large-scale (100 km ? 50 km) coordinated aircraft and AMSR-E snow depth measurements over portions of the Chukchi and Beaufort seas. This paper focuses on the latter part of the campaign. The P-3B aircraft carried the University of Colorado Polarimetric Scanning Radiometer (PSR-A), the NASA Wallops Airborne Topographic Mapper (ATM) lidar altimeter, and the University of Kansas Delay-Doppler (D2P) radar altimeter. The PSR-A was used as an AMSR-E simulator, whereas the ATM and D2P altimeters were used in combination to provide an independent estimate of snow depth. Results of a comparison between the altimeter-derived snow depths and the equivalent AMSR-E snow depths using PSR-A brightness temperatures calibrated relative to AMSR-E are presented. Data collected over a frozen coastal polynya were used to intercalibrate the ATM and D2P altimeters before estimating an altimeter snow depth. Results show that the mean difference between the PSR and altimeter snow depths is -2.4 cm (PSR minus altimeter) with a standard deviation of 7.7 cm. The RMS difference is 8.0 cm. The overall correlation between the two snow depth data sets is 0.59.

  7. Lost at Sea

    Institute of Scientific and Technical Information of China (English)

    Maya; Reid

    2011-01-01

    OVER the last several years,dozens of sea turtles have been washing up on the shores of Central Africa dead.Many of these creatures,olive ridley turtles,were adult females poised to breed. Most puzzling,though,is that these turtles are being found on protected beaches that belong to national parks both in Gabon and the Republic of the Congo. Olive ridleys are considered to be the most abundant sea turtles on the planet,with around 800,000 females nesting annually.They can be found around the globe,in places like China’s Hainan and Hong Kong,among others.In spite of their numbers,they are the world’s most exploited species of sea

  8. Indicators and SEA

    DEFF Research Database (Denmark)

    Gao, Jingjing; Kørnøv, Lone; Christensen, Per

    well as in communicative perspective. Developing indicators is both a political and professional process, and the paper finally discuss the need of selection criteria mentioned in the guidelines, and also gives some ideas on how to tackle the development of indicators being explicit about it both as a......Abstract: Indicators are widely used in SEA to measure, communicate and monitor impacts from a proposed policy, plan or programme, and can improve the effectiveness for the SEA by simplifying the complexity of both assessment and presentation. Indicators can be seen as part of the implementation...... process helping to understand, communicate and, integrate important environmental issues in planning and decision-making. On the other hand, use of indicators can also limit SEA effectiveness, if the ones chosen are biased or limited, if the aggregation gives incorrect interpretation and if the...

  9. Dynamics of sea level variations in the coastal Red Sea

    Science.gov (United States)

    Churchill, James; Abulnaja, Yasser; Nellayaputhenpeedika, Mohammedali; Limeburner, Richard; Lentz, Steven

    2016-04-01

    Sea level variations in the central Red Sea coastal zone span a range of roughly 1.2 m. Though relatively small, these water level changes can significantly impact the environment over the shallow reef tops prevalent in the central Red Sea, altering the water depth by a factor or two or more. While considerable scientific work has been directed at tidal and seasonal variations of Red Sea water level, very little attention has been given to elevation changes in an 'intermediate' frequency band, with periods of 2-30 d, even though motions in this band account for roughly half of the sea level variance in central Red Sea. We examined the sea level signal in this band using AVISO sea level anomaly (SLA) data, COARDAS wind data and measurements from pressure sensors maintained for more than five years at a number of locations in Saudi Arabian coastal waters. Empirical orthogonal function analysis of the SLA data indicates that longer-period (10-30 d) sea level variations in the intermediate band are dominated by coherent motions in a single mode that extends over most of the Red Sea axis. Idealized model results indicate that this large-scale mode of sea level motion is principally due to variations in the large-scale gradient of the along-axis wind. Our analysis indicates that coastal sea level motions at shorter periods (2-10 d) are principally generated by a combination of direct forcing by the local wind stress and forcing associated with large-scale wind stress gradients. However, also contributing to coastal sea level variations in the intermediate frequency band are mesoscale eddies, which are prevalent throughout the Red Sea basin, have a sea level signal of 10's of cm and produce relatively small-scale (order 50 km) changes in coastal sea level.

  10. Sea-level fluctuations and deep-sea sedimentation rates.

    Science.gov (United States)

    Worsley, T R; Davies, T A

    1979-02-01

    Sediment accumulation rate curves from 95 drilled cores from the Pacific basin and sea-level curves derived from continental margin seismic stratigraphy show that high biogenous sediment accumulation rates correspond to low eustatic sea levels for at least the last 48 million years. This relationship fits a simple model of high sea levels producing lower land/sea ratios and hence slower chemical erosion of the continents, and vice versa. PMID:17734144

  11. Skin disorders at sea.

    Science.gov (United States)

    Lucas, Ray; Boniface, Keith; Hite, Michael

    2010-01-01

    The purpose of this study is to characterize the types of skin disorders occurring at sea requiring acute treatment. The case logs of a tele-medicine service for US flagged ships at sea were reviewed from March 1, 2006 until March 1, 2009. Of 1844 total cases, 10% (n = 183) were for skin disorders. Sixty-eight percent (n = 125) were infections, 14% (n = 25) were inflammatory, 7% (n = 13) were environmental, and 11% (n = 20) were non-specific rashes. Cutaneous abscesses and cellulitis (n = 84) were the most common acute skin disorders encountered. In some cases (n = 81), still digital photographs aided in the diagnosis. PMID:20496321

  12. Seasonal Change of Steric Sea Level in the GIN Seas

    Institute of Scientific and Technical Information of China (English)

    LI Lei; WANG Huijuan; SUN Ruili

    2011-01-01

    The Greenland Sea, Iceland Sea, and Norwegian Sea (GIN seas) form the main channel connecting the Arctic Ocean with other Oceans, where significant water and energy exchange take place, and play an important role in global climate change. In this study steric sea level, associated with temperature and salinity, in the GIN seas is examined based on analysis of the monthly temperature and salinity fields from Polar science center Hydrographic Climatology (PHC3.0). A method proposed by Tabata et al. is used to calculate steric sea level, in which, steric sea level change due to thermal expansion and haline contraction is termed as the thermosteric component (TC) and the halosteric component (SC), recpectively. Total steric sea level (TSSL) change is the sum of TC and SC. The study shows that SC is making more contributions than TC to the seasonal change of TSSL in the Greenland Sea, whereas TC contributes more in the Norwegian and the Iceland Seas. Annual variation of TSSL is larger than 50ram over most regions of the GIN Seas, and can be larger than 200mm at some locations such as 308mm at 76.5°N, 12.5°E and 246mm at 77.50N, 17.5°W.

  13. SEA LEVEL (TOPEX/POSEIDON)

    Data.gov (United States)

    National Aeronautics and Space Administration — Sea level rise is caused by the thermal expansion of sea water due to climate warming and widespread melting of land ice. The TOPEX/POSEIDON mission a joint...

  14. Solomon's Sea and [Pi

    Science.gov (United States)

    Simoson, Andrew J.

    2009-01-01

    This paper is a whimsical survey of the various explanations which might account for the biblical passage in I Kings 7:23 that describes a round object--a bronze basin called Solomon's Sea--as having diameter ten cubits and circumference thirty cubits. Can the biblical pi be any number other than 3? We offer seven different perspectives on this…

  15. The Dirac Sea

    OpenAIRE

    Dimock, J.

    2010-01-01

    We give an alternate definition of the free Dirac field featuring an explicit construction of the Dirac sea. The treatment employs a semi-infinite wedge product of Hilbert spaces. We also show that the construction is equivalent to the standard Fock space construction.

  16. Solar Sea Power

    Science.gov (United States)

    Zener, Clarence

    1976-01-01

    In their preoccupation with highly complex new energy systems, scientists and statesmen may be overlooking the possibilities of Ocean Thermal Energy Conversion (OTEC). That is the view of a Carnegie-Mellon University physicist who is in the forefront of solar sea power investigation. (Author/BT)

  17. The Provident Sea

    Science.gov (United States)

    Cushing, David H.

    1988-09-01

    The Provident Sea describes the history of fish stock management (including whales and seals). The book traces, on the basis of the original scientific material, the history of the management of "the provident sea" up to recent times when problems of over-exploitation have had dramatic effects upon stocks. The need for management arose mainly from the increasing industrialization of capture. Hence the preindustrial fisheries are covered, in particular the old cod fishery on the Grand Bank and the herring fishery in the North Sea, as an essential background to current problems. The origins of fisheries and whaling science are described, as is the development up to 1965 of the science and institution in fisheries, whaling, and sealing. In the sixties and seventies, certain major fishing nations took a heavy harvest of fish stocks using sophisticated and efficient gathering methods. This in turn led to conflict and one consequence was the "Law of the Sea" conference set up to try and resolve these issues.

  18. Pollution around Malta's sea

    OpenAIRE

    Formosa, Nicolette; Duca, Edward

    2014-01-01

    Marine littering is a global concern and every single year tons of litter end up in the ocean all around the globe. It has become such a problem that the waste has amalgamated into huge ‘islands’ floating in the world’s oceans. http://www.um.edu.mt/think/pollution-around-maltas-sea/

  19. Baltic Sea: Radionuclides

    DEFF Research Database (Denmark)

    Nielsen, Sven Poul; Lüning, Maria; Ilus, Erkki;

    2010-01-01

    The most significant source of anthropogenic radioactivity in the Baltic Sea is fallout from the accident at the Chernobyl nuclear power plant in 1986. The second most important source is global fallout from atmospheric nuclear weapons tests carried out during the late 1950s and early 1960s. Radi...

  20. The Sea Beside Us

    Science.gov (United States)

    Watling, Carol; Hallard Raymond E.

    1974-01-01

    The Sea Beside Us for the Special Child is a project in Delaware with three goals: providing outdoor and overnight experiences for handicapped children; introducing these students to beach, bay, and marsh environments; and increasing the number of special education teachers incorporating seashore studies in their teaching curriculum. (LS)

  1. Sea-Level Projections from the SeaRISE Initiative

    Science.gov (United States)

    Nowicki, Sophie; Bindschadler, Robert

    2011-01-01

    SeaRISE (Sea-level Response to Ice Sheet Evolution) is a community organized modeling effort, whose goal is to inform the fifth IPCC of the potential sea-level contribution from the Greenland and Antarctic ice sheets in the 21st and 22nd century. SeaRISE seeks to determine the most likely ice sheet response to imposed climatic forcing by initializing an ensemble of models with common datasets and applying the same forcing to each model. Sensitivity experiments were designed to quantify the sea-level rise associated with a change in: 1) surface mass balance, 2) basal lubrication, and 3) ocean induced basal melt. The range of responses, resulting from the multi-model approach, is interpreted as a proxy of uncertainty in our sea-level projections. http://websrv.cs .umt.edu/isis/index.php/SeaRISE_Assessment.

  2. AFSC/RACE/EcoFOCI - Zooplankton data collected in support of FOCI assessment surveys and ecosystem observations in the Bering, Beaufort, and Chukchi Seas and the Gulf of Alaska, 1987 – Present

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton data are abundance by taxanomic group (to species where possible), stage, size and sex. Zooplankton sorting is performed at The Polish Plankton Sorting...

  3. Near-surface temperature profiles collected from an Arctic Wave Glider (AWG) near the Arctic ice-edge in the Beaufort Sea from July 29, 2011 to September 23, 2011 (NODC Accession 0088841)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data in the attached files are near-surface temperature profiles collected by an Arctic Wave Glider (AWG) from July 29-Sept 23, 2011. Temperatures were...

  4. Underway meteorological, navigational, physical and time series data collected aboard the NOAA Ship Ronald H. Brown in the Arctic Ocean, Beaufort Sea and others from 2015-08-06 to 2015-09-04 (NCEI Accession 0141104)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0141104 contains raw underway meteorological, navigational, physical and time series data logged by the Scientific Computer System (SCS) aboard the...

  5. Aerial surveys of bowhead and beluga whales along with incidental sighting of other marine mammals in the Bering, Beaufort and Chukchi Seas for the Bowhead Whale Aerial Survey Project (BWASP), 1979 - 2004 (NODC Accession 0001941)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Minerals Management Service (MMS), previously Bureau of Land Management, has funded fall bowhead whale aerial surveys in this area each year since 1978, using a...

  6. Aerial sightings of bowhead whales and other marine mammals by the US Department of the Interior's Minerals Management Service, 1979 - 2006, in the Bering, Chukchi and Beaufort Seas (NODC Accession 0014906)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Minerals Management Service (MMS), previously Bureau of Land Management, has funded fall bowhead whale aerial surveys in this area each year since 1978, using a...

  7. Physical, chemical, and biological data collected in the Beaufort Sea as part of the Arctic Nearshore Impact Monitoring in the Development Area (ANIMIDA) from 1999 to 2007 (NODC Accession 0001921)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data contains information specifically for the Arctic Nearshore Impact Monitoring in the Development Area (ANIMIDA 1999 - 2002) and continuation of Arctic...

  8. AFSC/RACE/EcoFOCI - Physical oceanographic data collected in support of EcoFOCI assessment surveys and ecosystem observations in the Bering, Beaufort, and Chukchi Seas and the Gulf of Alaska - 1995 to Present

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Pressure, temperature and salinity data. Data are available in 1 meter intervals in conjunction with the MARMAP 20/60 bongo array, CalVET, and Tucker trawl. Maximum...

  9. Aerial Surveys of Arctic Marine Mammals (ASAMM) collected by National Marine Mammal Laboratory, Bureau of Ocean Energy Management, and other agencies in the Bering, Chukchi and Beaufort Seas (NODC Accession 0039614)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains aerial survey data from the surveys described below. The Bureau of Ocean Energy Management (BOEM), formerly the Minerals Management...

  10. The sea is your mirror

    OpenAIRE

    Parenthoen, Marc; Murie, Fred; Thery, Flavien

    2015-01-01

    The Sea Is Your Mirror is an artistic interactive experience where surface cerebral electromagnetic waves from a participant wearing an EEG sensor headset are depicted in real-time as ocean waves in an animated 3D environment. The aim of this article is to describe the sea wave model used for the sea state animation and how it is connected to the brain computer interface (BCI). The sea state is animated by the groupy choppy wave model that provides nonlinear sea states with wave groups and as...

  11. Dead Sea Rate of Evaporation

    OpenAIRE

    Abdelaziz L. AL-Khlaifat

    2008-01-01

    The Dead Sea is exceptional by many standards. It is the saltiest and lowest lake in the world. Moreover it is a closed lake with very large variations in its water level caused by both man-made and natural oscillations of the components that make up the water balance. Most of the fundamental studies on the Dead Sea focused on the sea water contents, Dead Sea geology, salt origin, ground-water sea intrusion, and qualitative analysis of the material balance. The objective of the present paper ...

  12. Sea Spray Aerosols

    DEFF Research Database (Denmark)

    Butcher, Andrew Charles

    Aerosols are important climactically. Their specific emissions are key to reducing the uncertainty in global climate models. Marine aerosols make up the largest source of primary aerosols to the Earth's atmosphere. Uncertainty in marine aerosol mass and number flux lies in separating primary...... emissions produced directly from bubble bursting as the result of air entrainment from breaking waves and particles generated from secondary emissions of volatile organic compounds. In the first paper, we study the chemical properties of particles produced from several sea water proxies with the use of a...... cloud condensation nuclei ounter. Proxy solutions with high inorganic salt concentrations and some organics produce sea spray aerosol particles with little change in cloud condensation activity relative to pure salts. Comparison is made between a frit based method for bubble production and a plunging...

  13. Changing Sea Levels

    Science.gov (United States)

    Pugh, David

    2004-04-01

    Flooding of coastal communities is one of the major causes of environmental disasters world-wide. This textbook explains how sea levels are affected by astronomical tides, weather effects, ocean circulation and climate trends. Based on courses taught by the author in the U.K. and the U.S., it is aimed at undergraduate students at all levels, with non-basic mathematics being confined to Appendices and a website http://publishing.cambridge.org/resources/0521532183/.

  14. Wood decay at sea

    Science.gov (United States)

    Charles, François; Coston-Guarini, Jennifer; Guarini, Jean-Marc; Fanfard, Sandrine

    2016-08-01

    The oceans and seas receive coarse woody debris since the Devonian, but the kinetics of wood degradation remains one of many unanswered questions about the fate of driftwood in the marine environment. A simple gravimetric experiment was carried out at a monitoring station located at the exit of a steep, forested Mediterranean watershed in the Eastern Pyrenees. The objective was to describe and quantify, with standardized logs (in shape, structure and constitution), natural degradation of wood in the sea. Results show that the mass decrease of wood logs over time can be described by a sigmoidal curve. The primary process of wood decay observed at the monitoring station was due to the arrival and installation of wood-boring species that consumed more than half of the total wood mass in six months. Surprisingly, in a region where there is little remaining wood marine infrastructure, "shipworms", i.e. xylophagous bivalves, are responsible for an important part of this wood decay. This suggests that these communities are maintained probably by a frequent supply of a large quantity of riparian wood entering the marine environment adjacent to the watershed. By exploring this direct link between terrestrial and marine ecosystems, our long term objective is to determine how these supplies of terrestrial organic carbon can sustain wood-based marine communities as it is observed in the Mediterranean Sea.

  15. Simulations of Sea-Ice Dynamics Using the Material-Point Method

    Science.gov (United States)

    Sulsky, D.; Schreyer, H.; Peterson, K.; Nguyen, G.; Coon, G.; Kwok, R.

    2006-01-01

    provide similar overall deformation as the viscous-plastic model; however, explicit regions of opening and shear are predicted. Furthermore, the efficiency of MPM with the elastic-decohesive model is competitive with the current best methods for sea ice dynamics. Simulations will also be presented for an area of the Beaufort Sea, where predictions can be validated against satellite observations of the Arctic.

  16. Sea-Level climate variability in the Mediterranean Sea

    OpenAIRE

    Bonaduce, Antonio

    2012-01-01

    Sea-level variability is characterized by multiple interacting factors described in the Fourth Assessment Report (Bindoff et al., 2007) of the Intergovernmental Panel on Climate Change (IPCC) that act over wide spectra of temporal and spatial scales. In Church et al. (2010) sea-level variability and changes are defined as manifestations of climate variability and change. The European Environmental Agency (EEA) defines sea level as one of most important indicators for monitoring climate chan...

  17. Tectonics of Chukchi Sea Shelf sedimentary basins and its influence on petroleum systems

    Science.gov (United States)

    Agasheva, Mariia; Antonina, Stoupakova; Anna, Suslova; Yury, Karpov

    2016-04-01

    The Chukchi Sea Shelf placed in the East Arctic offshore of Russia between East Siberian Sea Shelf and North Slope Alaska. The Chukchi margin is considered as high petroleum potential play. The major problem is absence of core material from drilling wells in Russian part of Chukchi Shelf, hence strong complex geological and geophysical analyses such as seismic stratigraphy interpretation should be provided. In addition, similarity to North Slope and Beaufort Basins (North Chukchi) and Hope Basin (South Chukchi) allow to infer the resembling sedimentary succession and petroleum systems. The Chukchi Sea Shelf include North and South Chukchi Basins, which are separated by Wrangel-Herald Arch and characterized by different opening time. The North Chukchi basin is formed as a general part of Canada Basin opened in Early Cretaceous. The South Chukchi Basin is characterized by a transtensional origin of the basin, this deformation related to motion on the Kobuk Fault [1]. Because seismic reflections follow chronostratigraphic correlations, it is possible to achieve stratigraphic interpretation. The main seismic horizons were indicated as: PU, JU, LCU, BU, mBU marking each regional unconformities. Reconstruction of main tectonic events of basin is important for building correct geological model. Since there are no drilling wells in the North and South Chukchi basins, source rocks could not be proven. Referring to the North Chukchi basin, source rocks equivalents of Lower Cretaceous Pebble Shale Formation, Lower Jurassic Kingdak shales and Upper Triassic Shublik Formation (North Slope) is possible exhibited [2]. In the South Chukchi, it is possible that Cretaceous source rocks could be mature for hydrocarbon generation. Erosions and uplifts that could effect on hydrocarbon preservation was substantially in Lower Jurassic and Early Cretaceous periods. Most of the structures may be connected with fault and stratigraphy traps. The structure formed at Wrangel-Herald Arch to

  18. Alaska Phocid Argos Telemetry Archive (2004-2013)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Polar Ecosystems Program conducts research and monitoring on phocid seals in the East Bering Sea, West Bering Sea, Gulf of Alaska, Beaufort Sea, and Chukchi Sea...

  19. Sea level monitoring in Mozambique

    OpenAIRE

    Nhampulo, C.I.S.; Ruby, J,

    2002-01-01

    Observing changes in the rise of relative sea level has resulted from the balance between the sea level rise due to the global warming of the planet, and the vertical displacements of the coast due to geological movements. The main objective of this paper is to outsource information about sea level monitoring in Mozambique, as part of a common global effort aiming to colect and analyse data that can help in understanding physical processes envolving ocean basins or oceans as a hole. Tidal ...

  20. Air sea ratio reduction initiative

    Energy Technology Data Exchange (ETDEWEB)

    Oberle, Jean

    2010-09-15

    Airfreight is the most expensive mode of transportation as well as the most impacting in terms of CO{sup 2} emissions. It is 7 times more expensive on average to ship by air than shipping by sea 1. Airfreight transportation mode emits 30 times more CO{sup 2} than sea freight mode 2. These elements provided a compelling platform to design a global logistics program to initiate a modal shift from air to sea freight without compromising service to customers.

  1. Sea Otter, River Otter. The Wonder Series.

    Science.gov (United States)

    Robinson, Sandra Chisholm

    This curriculum guide is all about otters and provides information on both sea and river otters. Included are activities related to the diet of sea otters, the adaptations sea otters have made to live in the sea, their tool-using abilities, where they live and how to spot them, comparative anatomy of sea and river otters, and otter movement. The…

  2. Japan nuclear ship sea trial

    Energy Technology Data Exchange (ETDEWEB)

    Yamazaki, Hiroshi; Kitamura, Toshikatus; Mizushima, Toshihiko [Japan Atomic Energy Research Inst., Mutsu, Aomori (Japan). Mutsu Establishment] [and others

    1992-01-01

    The sea trial of the first Japan nuclear Ship `MUTSU` was conducted from the end of October to December in 1990. The purpose of the sea trial was to verify the nuclear propulsive performances and maneuverabilities. The present report describes the results of the sea trial. These results are classified into four items: 1. Speed test and engineering performance tests 2. Maneuvering performance tests 3. Vibration tests 4. Other tests. Acceptable performances were demonstrated, as expected in the original design. The experience of the use of the Global Positioning System (GPS), which were newly adopted for the sea trial, is also reported. (author).

  3. Japan nuclear ship sea trial

    Energy Technology Data Exchange (ETDEWEB)

    Yamazaki, Hiroshi; Kitamura, Toshikatus; Mizushima, Toshihiko (Japan Atomic Energy Research Inst., Mutsu, Aomori (Japan). Mutsu Establishment) (and others)

    1992-01-01

    The sea trial of the first Japan nuclear Ship 'MUTSU' was conducted from the end of October to December in 1990. The purpose of the sea trial was to verify the nuclear propulsive performances and maneuverabilities. The present report describes the results of the sea trial. These results are classified into four items: 1. Speed test and engineering performance tests 2. Maneuvering performance tests 3. Vibration tests 4. Other tests. Acceptable performances were demonstrated, as expected in the original design. The experience of the use of the Global Positioning System (GPS), which were newly adopted for the sea trial, is also reported. (author).

  4. Japan nuclear ship sea trial

    International Nuclear Information System (INIS)

    The sea trial of the first Japan nuclear Ship 'MUTSU' was conducted from the end of October to December in 1990. The purpose of the sea trial was to verify the nuclear propulsive performances and maneuverabilities. The present report describes the results of the sea trial. These results are classified into four items: 1. Speed test and engineering performance tests 2. Maneuvering performance tests 3. Vibration tests 4. Other tests. Acceptable performances were demonstrated, as expected in the original design. The experience of the use of the Global Positioning System (GPS), which were newly adopted for the sea trial, is also reported. (author)

  5. Heavy silicon isotopic composition of silicic acid and biogenic silica in Arctic waters over the Beaufort shelf and the Canada Basin

    Science.gov (United States)

    Varela, D. E.; Brzezinski, M. A.; Beucher, C. P.; Jones, J. L.; Giesbrecht, K. E.; Lansard, B.; Mucci, A.

    2016-06-01

    The silicon isotopic composition of silicic acid (δ30Si(OH)4) and biogenic silica (δ30Si-bSiO2) were measured for the first time in marine Arctic waters from the Mackenzie River delta to the deep Canada Basin in the late summer of 2009. In the upper 100 m of the water column, δ30Si(OH)4 signals (+1.82‰ to +3.08‰) were negatively correlated with the relative contribution of Mackenzie River water. The biogenic Si isotope fractionation factor estimated using an open system model, 30ɛ = -0.97 ± 0.17‰, agrees well with laboratory and global-ocean estimates. Nevertheless, the δ30Si dynamics of this region may be better represented by closed system isotope models that yield lower values of 30ɛ, between -0.33‰ and -0.41‰, depending on how the contribution of sea-ice diatoms is incorporated. In the upper 400 m, δ30Si-bSiO2 values were among the heaviest ever measured in marine suspended bSiO2 (+2.03‰ to +3.51‰). A positive correlation between δ30Si-bSiO2 and sea-ice cover implies that heavy signals can result from isotopically heavy sea-ice diatoms introduced to pelagic assemblages. Below the surface bSiO2 production zone, the δ30Si(OH)4 distribution followed that of major water masses. Vertical δ30Si(OH)4 profiles showed a minimum (average of +1.84 ± 0.10‰) in the upper halocline (125-200 m) composed of modified Pacific water and heavier average values (+2.04 ± 0.11‰) in Atlantic water (300-500 m deep). In the Canada Basin Deep Water (below 2000 m), δ30Si(OH)4 averaged +1.88 ± 0.12‰, which represents the most positive value ever measured anywhere in the deep ocean. Since most Si(OH)4 enters the Arctic from shallow depths in the Atlantic Ocean, heavy deep Arctic δ30Si(OH)4 signals likely reflect the influx of relatively heavy intermediate Atlantic waters. A box model simulation of the global marine δ30Si(OH)4 distribution successfully reproduced the observed patterns, with the δ30Si(OH)4 of the simulated deep Arctic Ocean being the

  6. AIR / SEA RESCUE LAUNCHES

    Directory of Open Access Journals (Sweden)

    W.H. Rice

    2012-02-01

    Full Text Available The Motor Boat Wing of the South African Air Force was inaugurated some thirty eight years ago.With its main base at Gordon's Bay, the wing was formed to operate the various marine craft used to provide a service to the flying component of the South African Air Force. Its main function was to be air/sea rescue, but it also had to man and maintain armoured target boats, seaplane tenders, marine tenders and the 'bomb scows', used for recovering practise bombs and missiles and for laying and lifting moorings.

  7. Deep-sea fungi

    Digital Repository Service at National Institute of Oceanography (India)

    Raghukumar, C.; Damare, S.

    • Institut fur Biotechno\\ogle. Biotechnikum. Walter Rathenau Strasse 49A, 17489GrcJf~wald.Germany. 265 266 Raghukumar and Damare from water samples collected from the subtropical Atlantic Ocean, from the surface to a depth of 4,500 m using sterile van Dom... Calcareous shells %5, Bay ofBengal 73 Only preserved specimens CFU CFt.: Chapter IS • Deep-Sea Fungi 267 fungi were isolated from surface-sterilized calcareous fragments collected from a depth of 300 to 860 m in the Bay of Bengal (73). These fungi were...

  8. Sea shore in Cyprus

    OpenAIRE

    2016-01-01

    Black and white photograph, showing a winter’s day at a deserted sea shore in Cyprus - Μαυρόασπρη κάρτ ποστάλ που απεικονίζει μια χειμωνιάτικη μέρα σε μια ερημική ακτή στην Κύπρο.

  9. The Sea Around Us

    Science.gov (United States)

    Carson, Rachel L.

    1991-12-01

    Published in 1951, The Sea Around Us is one of the most remarkably successful books ever written about the natural world. Rachel Carson's rare ability to combine scientific insight with moving, poetic prose catapulted her book to first place on The New York Times best-seller list, where it enjoyed wide attention for thirty-one consecutive weeks. It remained on the list for more than a year and a half and ultimately sold well over a million copies, has been translated into 28 languages, inspired an Academy Award-winning documentary, and won both the 1952 National Book Award and the John Burroughs Medal. This classic work remains as fresh today as when it first appeared. Carson's writing teems with stunning, memorable images--the newly formed Earth cooling beneath an endlessly overcast sky; the centuries of nonstop rain that created the oceans; giant squids battling sperm whales hundreds of fathoms below the surface; and incredibly powerful tides moving 100 billion tons of water daily in the Bay of Fundy. Quite simply, she captures the mystery and allure of the ocean with a compelling blend of imagination and expertise. Reintroducing a classic work to a whole new generation of readers, this Special Edition features a new chapter written by Jeffrey Levinton, a leading expert in marine ecology, that brings the scientific side of The Sea Around Us completely up to date. Levinton incorporates the most recent thinking on continental drift, coral reefs, the spread of the ocean floor, the deterioration of the oceans, mass extinction of sea life, and many other topics. In addition, acclaimed nature writer Ann Zwinger has contributed a brief foreword. Today, with the oceans endangered by the dumping of medical waste and ecological disasters such as the Exxon oil spill in Alaska, this illuminating volume provides a timely reminder of both the fragility and the importance of the ocean and the life that abounds within it. Anyone who loves the sea, or who is concerned about our

  10. Two Sea-Level Challenges

    Science.gov (United States)

    Galvin, C.

    2008-12-01

    "No place on the sandy ocean shores of the world has been shown to be eroding because of sea level rise." This statement appeared nearly 19 years ago in bold print at the top of the page in a brief article published in Shore and Beach (Galvin,1990). The term "sea level rise" was defined in 1990 as follows: "In this statement, "sea level rise" has the meaning that the average person on the street usually attaches to that term. That is, sea level is rising; not, as in some places like the Mississippi River delta, land level is sinking." While still a subject of controversy, it is now (2008) increasingly plausible (Tornqvist et al,2008) that damage from Hurricane Katrina was significantly worse on the Mississippi River delta because floodwaters exploited wetlands and levees whose elevations had been lowered by decades of compaction in the underlying soil. (1) "Sea level" commonly appears in the literature as "relative sea level rise", occurring that way in 711 publications between 1980 and 2009 (GeoRef database on 8 Sep 08). "Relative sea level rise" does not appear in the 2005 AGI Glossary. The nearest Glossary term is "relative change in sea level", but that term occurs in only 12 publications between 1980 and 2009. The Glossary defines this term in a sequence stratigraphy sense, which infers that "relative sea level rise" is the sum of bottom subsidence and eustatic sea level rise. In plain English, "relative sea level rise" means "water depth increase". For present day coastal environments, "relative sea level rise" is commonly used where eustatic sea level rise is less than subsidence, that is, where the magnitude of actual sea level rise is smaller than the magnitude of subsidence. In that situation, "relative sea level rise" misleads both the average person and the scientist who is not a coastal geologist. Thus, the first challenge is to abandon "relative sea level rise" in favor of "water depth increase", in order that the words accurately descibe what happens

  11. Deep sea biophysics

    International Nuclear Information System (INIS)

    A collection of deep-sea bacterial cultures was completed. Procedures were instituted to shelter the culture collection from accidential warming. A substantial data base on the rates of reproduction of more than 100 strains of bacteria from that collection was obtained from experiments and the analysis of that data was begun. The data on the rates of reproduction were obtained under conditions of temperature and pressure found in the deep sea. The experiments were facilitated by inexpensively fabricated pressure vessels, by the streamlining of the methods for the study of kinetics at high pressures, and by computer-assisted methods. A polybarothermostat was used to study the growth of bacteria along temperature gradients at eight distinct pressures. This device should allow for the study of microbial processes in the temperature field simulating the environment around buried HLW. It is small enough to allow placement in a radiation field in future studies. A flow fluorocytometer was fabricated. This device will be used to determine the DNA content per cell in bacteria grown in laboratory culture and in microorganisms in samples from the ocean. The technique will be tested for its rapidity in determining the concentration of cells (standing stock of microorganisms) in samples from the ocean

  12. EASE-Grid Sea Ice Age

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides weekly estimates of sea ice age for the Arctic Ocean from remotely sensed sea ice motion and sea ice extent. The ice age data are derived...

  13. Neutrino sea scope takes shape

    Science.gov (United States)

    Cartlidge, Edwin

    2016-03-01

    A consortium of European physicists building a vast neutrino detector on the floor of the Mediterranean Sea has unveiled the science it will carry out. The Cubic Kilometre Neutrino Telescope (KM3NeT) will use strings of radiation detectors arranged in a 3D network to measure the light emitted when neutrinos very occasionally interact with the surrounding sea water.

  14. Scaling the Baltic Sea environment

    DEFF Research Database (Denmark)

    Larsen, Henrik Gutzon

    2008-01-01

    The Baltic Sea environment has since the early 1970s passed through several phases of spatial objectification in which the ostensibly well-defined semi-enclosed sea has been framed and reframed as a geographical object for intergovernmental environmental politics. Based on a historical analysis of...

  15. Governance of the Wadden Sea

    NARCIS (Netherlands)

    Slob, Adriaan F.L.; Geerdink, T.R.A.; Rockmann, Christine; Vöge, S.

    2016-01-01

    The Wadden Sea is a unique area from ecological, geological and cultural perspectives and lies in the territories of Denmark, Germany and the Netherlands. The trilateral cooperation on the protection of the Wadden Sea can be marked to start in 1978, although the countries already cooperated befor

  16. The Sea Trout Year 1985

    OpenAIRE

    Fahy, E

    1986-01-01

    The wet year of 1985 yielded good catches to the rod and to commercial engines. Salmon were taken in reasonable numbers in the drift nets although only small numbers of sea trout were captured by this method. The wet angling season is thought to have provided productive fishing conditions contributing largely to a 22% increase over the previous year's landings of sea trout.

  17. Pollution of the North Sea

    International Nuclear Information System (INIS)

    This is the first modern review on the fate, distribution and effects of pollutants in the North Sea. The reader will find general information on the North Sea system and details on the behavior of pollutants and their impact on selected areas and organisms. (orig.) With 238 figs

  18. Sea level and climate variations

    NARCIS (Netherlands)

    Oerlemans, J.

    1985-01-01

    Review paper, ESA Symposium on Application of Satellite Data to Climate Modelling. Alpbach (Austria) Sea level is an essential component of the climate system, on which many human activities in the coastal zone depend. Climate variations leading to changes in relative sea level are discussed, with

  19. First oceanographic observations on the Wandel Sea shelf in Northeast Greenland: Tracing the Arctic Ocean outflow through the western Fram Strait

    Science.gov (United States)

    Dmitrenko, Igor A.; Kirillov, Sergei A.; Rudels, Bert; Babb, David G.; Pedersen, Leif T.; Rysgaard, Soeren; Kristoffersen, Yngve; Barber, David G.

    2016-04-01

    The first-ever conductivity-temperature-depth (CTD) observations on the Wandel Sea shelf in North Eastern Greenland were collected from the land-fast ice in April-May 2015 as a part of the Arctic Science Partnership collaboration during the first research campaign at the Villum Research Station. They were complemented by (i) the ice-tethered profiler (ITP) and Acoustic Dopler Current Profiler (ADCP) mooring observations in ~300 m of the tidewater glacier outlet from the Flade Isblink Ice Cap and (ii) CTDs taken in June-July 2015 along the Wandel Sea continental slope during the Norwegian FRAM 2014-15 sea ice drift. The CTD profiles deeper than 100 m are used to reveal the origin of water masses and determine the extent to which these water masses have interacted with ambient water from the continental slope. The subsurface water layer from ~20-70 m depth is comprised of freshened water (30-32 psu) that is likely associated with the Pacific Water outflow from the Arctic Ocean through the western Fram Strait. The underlying halocline layer centered at ~80 m (~33 psu) separates the Pacific Water layer from a deeper (Fram Strait. The Atlantic Water layer with temperature above 0°C is recorded below 140 m. Over the outer shelf, the halocline layer shows numerous cold density-compensated intrusions indicating lateral interaction with an ambient Polar Water mass across the continental slope. Mooring data shows an enhanced shelf-slope interaction responding the storm event in 23-24 April 2015 with northerly winds exceeding 10 m/s. The on-shelf transport of a cold and turbid water from the upper continental slope results in enhanced interleaving within the depth range of the halocline layer (~70-100 m). Our observations of Pacific Water in the Wandel Sea subsurface layer are set in the context of upstream observations in the Beaufort Sea for 2002-2011 and downstream observations from the Northeast Water Polynya (1992-1993), and clearly show the modification of Pacific

  20. FLOATING CRANE RESPONSE IN SEA WAVES

    OpenAIRE

    Čorić, Većeslav; Ćatipović, Ivan; Slapničar, Vedran

    2014-01-01

    Many activities present in the offshore technology are affected by sea waves and their safety strongly depends on the sea state. The fundamental question in operation risk analysis is the limit sea state which enables the safe operation controlled in all phases: from the sea surface to the sea bottom. The safe limit sea state is especially important when some lifting operation is performed in sea waves. This paper presents a dynamical model of a floating crane in sea waves with a hanging load...

  1. Measuring the thicknesses of the freshwater-layer plume and sea ice in the land-fast ice region of the Mackenzie Delta using helicopter-borne sensors

    Science.gov (United States)

    Prinsenberg, S. J.; Peterson, I. K.; Holladay, J. S.

    2008-12-01

    Helicopter-borne sensors have been used since the early 1990s to monitor ice properties in support of winter marine transportation along the east coast of Canada. The observations are used in ice chart production and to validate ice hazard identification algorithms using satellite advanced synthetic aperture radar (ASAR) imagery. In this study we evaluated the sensors' additional capability to monitor the freshwater plume characteristic beneath land-fast ice. During the Canadian Arctic Shelf Exchange Study (CASES) data were collected over the Mackenzie Delta in the southern Beaufort Sea where a buoyant river plume exists. Results showed that the electromagnetic-laser system could describe not only the ice properties but also the horizontal distribution of the freshwater plume depths that decreased in depth stepwise offshore as the flow of the buoyant plume was restricted by a series of ridge-rubble fields running parallel to the coast. Relative to the 2 m mean ice thickness, the plume layer depth varied from zero under mobile offshore pack ice to 3 m inshore of the third set of ridge-rubble fields.

  2. Uranium from sea water

    International Nuclear Information System (INIS)

    The prevalent situation in the field of uranium extraction from the oceans was reviewed from a scientific and technological standpoint and as to legality too. No international convention seems to limit the access to dissolved or suspended matter in free area of the oceans. All publications received through 1979 point to adsorption as the method of choice, at some form of hydrated titanium ''oxide'' as the most promising sorbent, and, generally spoken, at the cost of pumping water through the contacting system as a huge economical problem. A recent Swedish invention may circumvent the pumping problem by making available, in a previously unknown manner, some kind of self-renewing energy from the oceans. A simple economic calculus has resulted in costs from two to six times the present world market price of crude uranium oxide (which is assumed to be US dollar 43.-/1b), with a possibility to compete really after some technical and systematic developments. Results from a small-scale adsorption experiment in genuine sea water are presented: During a few weeks sea water was pumped through tiny, 10 cm high beds of sodium titanate ion exchangers, partly in the hydrogen form. The grain size was 250-500 μm, the flow rate 0.15-0.61 m/min. About 5% of the total amount of uranium passing the columns was retained, resulting in 8-11 μg/Ug. Also, large amounts of manganese, strontium, vanadium and zink were retained. Some of these elements and plankton as well may perhaps be recovered with an economic gain

  3. Role of sea ice in air-sea exchange and its relation to sea fog

    Institute of Scientific and Technical Information of China (English)

    解思梅; 包澄澜; 姜德中; 邹斌

    2001-01-01

    Synchronous or quasi-synchronous stereoscopic sea-ice-air comprehensive observation was conducted during the First China Arctic Expedition in summer of 1999. Based on these data, the role of sea ice in sea-air exchange was studied. The study shows that the kinds, distribution and thickness of sea ice and their variation significantly influence the air-sea heat exchange. In floating ice area, the heat momentum transferred from ocean to atmosphere is in form of latent heat; latent heat flux is closely related to floating ice concentration; if floating ice is less, the heat flux would be larger. Latent heat flux is about 21 23.6 W*m-2, which is greater than sensible heat flux. On ice field or giant floating ice, heat momentum transferred from atmosphere to sea ice or snow surface is in form of sensible heat. In the floating ice area or polynya, sea-air exchange is the most active, and also the most sensible for climate. Also this area is the most important condition for the creation of Arctic vapor fog. The heat exchange of a large-scale vapor fog process of about 500000 km2 on Aug. 21 22,1999 was calculated; the heat momentum transferred from ocean to air was about 14.8×109 kW. There are various kinds of sea fog, radiation fog, vapor fog and advection fog, forming in the Arctic Ocean in summer. One important cause is the existence of sea ice and its resultant complexity of both underlying surface and sea-air exchange.

  4. Rapid sea-level rise

    Science.gov (United States)

    Cronin, Thomas M.

    2012-11-01

    Several global and regional factors contribute to observed sea-level change along any particular coast. Global processes include changes in ocean mass (glacio-eustasy from ice melt), ocean volume (steric effects), viscoelastic land movements (glacioisostatic adjustment GIA), and changes in terrestrial water storage. Regional processes, often connected to steric and glacial changes, include changes in ocean circulation (Meridional Overturning Circulation [MOC]), glacial melting, local GIA, regional subsidence and others. Paleoclimate, instrumental and modeling studies show that combinations of these factors can cause relatively rapid rates of sea-level rise exceeding 3 mm yr-1 over various timescales along particular coasts. This paper discusses patterns and causes of sea-level rise with emphasis on paleoclimatological records. It then addresses the hypothesis of late Holocene (pre-20th century) sea-level stability in light of paleoclimatic evidence, notably from reconstructions of sea-surface temperature and glacial activity, for significant climate and sea-level variability during this time. The practical difficulties of assessing regional sea-level (SL) patterns at submillennial timescales will be discussed using an example from the eastern United States.

  5. The Kerr-Fermi Sea

    CERN Document Server

    Hartman, Thomas; Strominger, Andrew

    2009-01-01

    The presence of a massive scalar field near a Kerr black hole is known to produce instabilities associated with bound superradiant modes. In this paper we show that for massive fermions, rather than inducing an instability, the bound superradiant modes condense and form a Fermi sea which extends well outside the ergosphere. The shape of this Fermi sea in phase space and various other properties are analytically computed in the semiclassical WKB approximation. The low energy effective theory near the black hole is described by ripples in the Fermi surface. Expressions are derived for their dispersion relation and the effective force on particles which venture into the sea.

  6. Towards Good Order at Sea

    DEFF Research Database (Denmark)

    Mandrup, Thomas; Vreÿ, Francois

    structural problems facing attempts to create and maintain good order at sea off East Africa. As mentioned in one of the chapters, the most secure place for a criminal in East Africa to be is at sea, because most African littoral states have only limited capacity to police their territorial waters. The...... problems originating from the resultant “bad order at sea” can be directly felt on land, when smuggling, terrorism and related criminal activities operate more or less unhindered. The book provides an important mapping of the challenges preventing good order at sea off the African coast and East Africa in...

  7. Advantages of North Sea Assets

    International Nuclear Information System (INIS)

    The North Sea is a significant hydrocarbon province and any large multinational will need to maintain North Sea assets within their portfolio - as indeed they do. The general feeling that pervades the oil industry that the North Sea is ''mature'' can be demonstrated by reference to the facts. The result is a potential fall-off in activity and a serious threat to the future levels of profitability in the region. Notwithstanding the continuing development of large fields, such as Troll, of or multi-field developments, for example BP's recent announcement on ETAPs, activity is beginning to fall, most noticeably at the front end of the development cycle, in exploration. (author)

  8. Summer sea ice characteristics of the Chukchi Sea

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    During August 1999, we investigated sea ice characteristics; its distribution, surface feature, thickness, ice floe movement, and the temperature field around inter-borders of air/ice/seawater in the Chukchi Sea. Thirteen ice cores were drilled at 11 floe stations in the area of 72°24′ 77°18′N, 153°34′ 163°28′W and the ice core structure was observed. From field observation, three melting processes of ice were observed; surface layer melting, surface and bottom layers melting, and all of ice melting. The observation of temperature fields around sea ice floes showed that the bottom melting under the ice floes were important process. As ice floes and open water areas were alternately distributed in summer Arctic Ocean; the water under ice was colder than the open water by 0.4 2.8℃. The sun radiation heated seawater in open sea areas so that the warmer water went to the bottom when the ice floes move to those areas. This causes ice melting to start at the bottom of the ice floes. This process can balance effectively the temperature fluctuating in the sea in summer. From the crystalline structure of sea ice observed from the cores, it was concluded that the ice was composed of ice crystals and brine-ice films. During the sea ice melting, the brine-ice films between ice crystals melted firstly; then the ice crystals were encircled by brine films; the sea ice became the mixture of ice and liquid brine. At the end of melting, the ice crystals would be separated each other, the bond between ice crystals weakens and this leads to the collapse of the ice sheet.

  9. AoA Region: South Asian Seas

    Digital Repository Service at National Institute of Oceanography (India)

    Naqvi, S.W.A.

    The South Asian Seas region lies in the northern extreme of the Indian Ocean. It includes the Arabian Sea and Bay of Bengal Large Marine Ecosystems (LME) along with their marginal basins as well as the Laccadive Sea and the Andaman Sea. Counties...

  10. Baltic sea level low-frequency variability

    OpenAIRE

    Kulikov, Evgueni A.; Medvedev, Igor P.; Koltermann, Klaus Peter

    2015-01-01

    The low-frequency sea level spectrum in the Baltic Sea has been analysed based on long-term time series of sea level data (15–124 yr) from three tide gauge stations in the Baltic Sea and two stations in the North Sea. The principal periodicities detected in the spectrum are seasonal and tidal oscillations including the pole tide with a period of about 14 months. Cross-spectral analysis has been applied to estimate the frequency response of sea level oscillations in the Baltic Sea relative to ...

  11. Euthanasia across the North Sea

    OpenAIRE

    Rigter, Henk; Borst-Eilers, Els; Leenen, H J J

    1988-01-01

    The United Kingdom and The Netherlands are separated by a narrow stretch of sea but in terms of an understanding of euthanasia they seem to be light years apart. An attempt to bridge the information gap seems in order.

  12. The Maastrichtian sea level rise

    OpenAIRE

    Gullentops, F.

    1986-01-01

    The maximum sea level rise during the Maastrichtian has been much less than the 500 m claimed by some recent authors on this subject. Sedimentological and geomorphological arguments against such an hypothesis are forwarded.

  13. Sea otter studies in Alaska

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The final objective of the present Fish and Wildlife sea otter program is to learn enough of the ecology, population, reproductive potential, and requirements in...

  14. ROE Absolute Sea Level Changes

    Data.gov (United States)

    U.S. Environmental Protection Agency — This raster dataset represents changes in absolute sea level along U.S. coasts from 1993 to 2014. Data were provided by the University of Colorado at Boulder (2015)...

  15. Sea bed mapping and inspection

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    The conference has 24 presentations on the topics: Sea bed mapping, inspection, positioning, hydrography, marine archaeology, remote operation vehicles and computerized simulation technologies, oil field activities and plans, technological experiences and problems. (tk)

  16. Sea Turtle Cold Stun Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This spreadsheet includes data on sea turtle cold stun strandings from 2001 to present. These data include field number, species, stranding date, turtle...

  17. Sea Surface Temperature Climate Data Record for the North Sea and Baltic Sea

    DEFF Research Database (Denmark)

    Høyer, Jacob L.; Karagali, Ioanna

    2016-01-01

    A 30-yr climate data record (CDR) of sea surface temperature (SST) has been produced with daily gap-free analysis fields for the North Sea and the Baltic Sea region from 1982 to 2012 by combining the Pathfinder AVHRR satellite data record with the Along-Track Scanning Radiometer (ATSR) Reprocessing...... ARC observations on average. Validation against independent in situ observations shows a very stable performance of the data record, with a mean difference of -0.06 °C compared to moored buoys and a 0.46 °C standard deviation of the differences. The mean annual biases of the SST CDR are small for all...

  18. Sea Level Threat in Tuvalu

    Directory of Open Access Journals (Sweden)

    Than Aung

    2009-01-01

    Full Text Available Problem statement: Recently the impacts of climate change, in particular, sea level rise, had been a major concern for many Pacific island countries. In early 2000, there were a series of media coverage over sea level rise issues using Tuvalu as an example. The daily life of Tuvalu revolves around the ocean and the immediate threat on the islands people, economy, environment and its islands is of concern to the Tuvalu government. The Tuvalu government has concluded that Tuvalu was destined to become the first nation to be sunk by global warming because it is one of the smallest and lowest-lying countries in the world. Approach: In this study, sea level data from the Australian project will be focussed on despite the fact that the length of data is not sufficiently long. The AusAID funded South Pacific Sea Level and climate monitoring project was set up in response to concerns raised by Pacific island countries over the potential impacts of an enhanced greenhouse effect on climate and sea levels in the South Pacific for 20 years. Results: Based upon the 15½ years of sea level data from the project, the sea level rise rate in Tuvalu as at september 2008 was 5.9 mM year-1. This was about four times higher than the global average of 1-2 mm year-1. Sea level in the Tuvalu area had risen approximately 9.14 cm since the inception of the project 15½ years ago. However, it was to be noted that the land is quite stable and the rate of land sinking is -0.06 mM year-1 only. Accordingly, there was no significant impact on the sea level trends. Conclusion: Although the data length is just over 15 years, the sea level trend values do not fluctuate significantly since 1999. It simply indicated that the rate of sea level rise in the Tuvalu region was not accelerating as anticipated by the community.

  19. Sea Level Threat in Tuvalu

    OpenAIRE

    Than Aung; Awnesh Singh; Uma Prasad

    2009-01-01

    Problem statement: Recently the impacts of climate change, in particular, sea level rise, had been a major concern for many Pacific island countries. In early 2000, there were a series of media coverage over sea level rise issues using Tuvalu as an example. The daily life of Tuvalu revolves around the ocean and the immediate threat on the islands people, economy, environment and its islands is of concern to the Tuvalu government. The Tuvalu government has concluded that Tuvalu was destined to...

  20. Respiration in Neonate Sea Turtles

    OpenAIRE

    Price, Edwin R.; Paladino, Frank V.; Strohl, Kingman P.; Pilar Santidrián, T.; Klann, Kenneth; Spotila, James R.

    2006-01-01

    The pattern and control of respiration is virtually unknown in hatchling sea turtles. Using incubator-raised turtles, we measured oxygen consumption, frequency, tidal volume, and minute volume for leatherback (Dermochelys coriacea) and olive ridley (Lepidochelys olivacea) turtle hatchlings for the first six days after pipping. In addition, we tested the hatchlings’ response to hypercapnic, hyperoxic, and hypoxic challenges over this time period. Hatchling sea turtles generally showed resting ...

  1. Studies on sea snake venom

    OpenAIRE

    TAMIYA, Nobuo; YAGI, Tatsuhiko

    2011-01-01

    Erabutoxins a and b are neurotoxins isolated from venom of a sea snake Laticauda semifasciata (erabu-umihebi). Amino acid sequences of the toxins indicated that the toxins are members of a superfamily consisting of short and long neurotoxins and cytotoxins found in sea snakes and terrestrial snakes. The short neurotoxins to which erabutoxins belong act by blocking the nicotinic acetylcholine receptor on the post synaptic membrane in a manner similar to that of curare. X-ray crystallography an...

  2. Bioactive molecules from sea hares.

    Science.gov (United States)

    Kamiya, H; Sakai, R; Jimbo, M

    2006-01-01

    Sea hares, belonging to the order Opisthobranchia, subclass Gastropoda, are mollusks that have attracted many researchers who are interested in the chemical defense mechanisms of these soft and "shell-less" snails. Numbers of small molecules of dietary origin have been isolated from sea hares and some have ecologically relevant activities, such as fish deterrent activity or toxicity. Recently, however, greater attention has been paid to biomedically interesting sea hare isolates such as dolastatins, a series of antitumor peptide/macrolides isolated from Dolabella auricularia. Another series of bioactive peptide/macrolides, as represented by aplyronines, have been isolated from sea hares in Japanese waters. Although earlier studies indicated the potent antitumor activity of aplyronines, their clinical development has never been conducted because of the minute amount of compound available from the natural source. Recent synthetic studies, however, have made it possible to prepare these compounds and analogs for a structure-activity relationship study, and started to uncover their unique action mechanism towards their putative targets, microfilaments. Here, recent findings of small antitumor molecules isolated from Japanese sea hares are reviewed. Sea hares are also known to produce cytotoxic and antimicrobial proteins. In contrast to the small molecules of dietary origin, proteins are the genetic products of sea hares and they are likely to have some primary physiological functions in addition to ecological roles in the sea hare. Based on the biochemical properties and phylogenetic analysis of these proteins, we propose that they belong to one family of molecule, the "Aplysianin A family," although their molecular weights are apparently divided into two groups. Interestingly, the active principles in Aplysia species and Dolabella auricularia were shown to be L-amino acid oxidase (LAAO), a flavin enzyme that oxidizes an alpha-amino group of the substrate with

  3. Artificial radioactivity in the North Sea

    International Nuclear Information System (INIS)

    The question of radioactive contamination of the environment is a problem of world-wide importance. The North Sea is an important example of a sea region heavily used by man and therefore polluted by different contaminants including radionuclides. A review of the present knowledge of the radiological situation of the North Sea and adjacent sea regions is given. The sources of artificial radionuclides and their distribution, behaviour and fate in this shallow sea area are discussed. (author)

  4. Evaporation of Boric Acid from Sea Water

    OpenAIRE

    Gast, James A.; Thompson, Thomas G.

    2011-01-01

    Previous investigators have shown that the boron-chlorinity ratios of rain waters are many times greater than the boron-chlorinity ratio of sea water. The presence of boron in the atmosphere has been attributed to sea spray, volcanic activity, accumulation in dust, evaporation from plants, and industrial pollution. In this paper data are presented to demonstrate that boric acid in sea water has a vapor pressure at ordinary temperatures of the sea and, when sea water evaporates, boric acid occ...

  5. Intermittent sea-level acceleration

    Science.gov (United States)

    Olivieri, M.; Spada, G.

    2013-10-01

    Using instrumental observations from the Permanent Service for Mean Sea Level (PSMSL), we provide a new assessment of the global sea-level acceleration for the last ~ 2 centuries (1820-2010). Our results, obtained by a stack of tide gauge time series, confirm the existence of a global sea-level acceleration (GSLA) and, coherently with independent assessments so far, they point to a value close to 0.01 mm/yr2. However, differently from previous studies, we discuss how change points or abrupt inflections in individual sea-level time series have contributed to the GSLA. Our analysis, based on methods borrowed from econometrics, suggests the existence of two distinct driving mechanisms for the GSLA, both involving a minority of tide gauges globally. The first effectively implies a gradual increase in the rate of sea-level rise at individual tide gauges, while the second is manifest through a sequence of catastrophic variations of the sea-level trend. These occurred intermittently since the end of the 19th century and became more frequent during the last four decades.

  6. DESERVE - Dead Sea Research Venue

    Science.gov (United States)

    Mohsen, A.; Weber, M. H.; Kottmeier, C.

    2013-12-01

    DESERVE 'Dead Sea Research Venue' focuses on the Dead Sea region as it is a unique environment and may be considered as one of the most inspiring natural laboratories on Earth. The Dead Sea Region is an exceptional ecosystem whose seismic activity has influenced all facets of the development, from ground water availability to human evolution. DESERVE addresses three grand challenges: Environmental Risks, Water Availability, Climate Change and comprises long term monitoring of geophysical parameters, studies of coupled processes in the atmosphere, hydrosphere and lithosphere as well as modeling of prediction and remediation strategies of geogenic risks. The Dead Sea has been selected for this integrated approach because it constitutes an outstanding 'natural laboratory' to study these phenomena, as - all 3 challenges are critical in this region. - the region is especially sensitive to climate change and human influences such as ground and surface water over-exploitation for agriculture and industrial purposes. - environmental processes are subject to boundary conditions that cannot be found elsewhere on Earth - understanding their interactions and the future evolution of the whole Dead Sea region are of key importance for economic development in peaceful cooperation. Results obtained in the Dead Sea region are also of prototype relevance for other (semi)-arid terminal basins of the world.

  7. Alien seas oceans in space

    CERN Document Server

    Lopes, Rosaly

    2013-01-01

    In the early days of planetary observation, oceans were thought to exist in all corners of the Solar System. Carbonated seas percolated beneath the clouds of Venus. Features on the Moon's surface were given names such as "the Bay of Rainbows” and the "Ocean of Storms." With the advent of modern telescopes and spacecraft exploration these ancient concepts of planetary seas have been replaced by the reality of something even more exotic. Alien Seas serves up the current research, past beliefs, and new theories to offer a rich array of the "seas" on other worlds. It is organized by location and by the material composing the oceans under discussion, with expert authors penning chapters on their  specialty. Each chapter features new original art depicting alien seas, as well as the latest ground-based and spacecraft images. With the contributors as guides, readers can explore the wild seas of Jupiter's watery satellite Europa, believed similar in composition to battery acid. Saturn's planet-sized moon Titan see...

  8. Sea otter investigation, Amchitka Island, 1954, and proposed plan of research for sea otters

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report describes a sea otter investigation on Amchitka Island during 1954 and a proposed plan of research for sea otters. The report covers capturing wild sea...

  9. Variability In The Solomon Sea From Altimetric Sea Level Data

    Science.gov (United States)

    Melet, A.; Gourdeau, L.; Kessler, W.; Verron, J.

    2007-12-01

    In the southwest tropical Pacific, subtropical waters from the SEC flow in the Solomon Sea, mainly through the western boundary New Guinea Coastal Undercurrent, and join the equatorial western Pacific by three narrow straits. The NGCU transports part of the spiciness anomalies generated in the South East Pacific and subducted in the thermocline. Because the NGCU is a primary source of the EUC, variations of its characteristics are expected to play a role in the equatorial thermocline features and more generally on decadal climate variability. Therefore, the study of the Solomon Sea is a key issue of the SPICE program. In this study, we focus on the variability of the Solomon Sea in term of sea level. The Solomon Sea is semi closed with a complex topography and numerous islands. Thus, the use of classical gridded altimetric products is inadequate. Consequently, this work is based on original along track Topex/Poseidon data. New data processing (CTOH/LEGOS) has been applied to recover proper data and to gain more information on the altimetric signal in this region. A track-by-track specific and customized post processing has been used to finalize the dataset. These new altimetric data have been assessed against tide gauge data. The analysis of the resulting sea level anomalies exhibits the highest variability observed in the tropical Pacific in an area centred near 8°S and expanding from each side of the Solomon Islands, outside of the WBC. Sea level variability presents a wide temporal spectrum, from intraseasonal to interannual ranges with the notable influence of the monsoon and of ENSO. In the Solomon Sea, three frequencies emerge : 60, 365 and 2000 days. The 60-days frequency seems particularly important in the Solomon Sea compared with the surrounding waters and an EOF analysis is used to understand its features. We also depict the signature of the New Guinea Coastal Current (NGCC), the western boundary current flowing north along the eastern coast of Papua

  10. Sea level pressure climatology in black sea region

    Directory of Open Access Journals (Sweden)

    Sayed Mohammad Hosseini

    2014-02-01

    Full Text Available In the present study, to achieve a comprehensive view of pressure conditions in the Black Sea region, sea level pressure data in Reanalysis II database in National Centers for Environmental Prediction (NCEP/National Center for Atmospheric Research (NCAR were used. The data temporal resolution is daily and the spatial resolution is 2.5×2.5 degrees of arc. The investigated framework covers the areas between -30-70 degrees east longitude and 20-70 degrees north latitude and has dimensions equal 41×21 pixels consisting of 861 pixels. The studied period of time is 33-year (1979 to 2012 and includes 12419 days and 861 spatial pixels. Therefore, sea level pressure data matrix is 12419×861, which has 12419 temporal pixels and 861 spatial ones. In other words, the arrangement of the data is S-shaped. The rows of the matrix represent time while columns represent space. At the end, using the cluster analysis, six sea level pressure circulation patterns based on the spatial - temporal features were obtained: Red Sea trough is fall pattern; Iraq trough is spring pattern; Persian Gulf trough is transitional pattern; Persian Gulf deep trough is summer pattern; Caucasian high pressure is fall - winter pattern and the Caucasian Strong high pressure is winter pattern. In most of these patterns, intensive allobaric conditions can be observed in the troughs and ridges.

  11. Deep-sea Hexactinellida (Porifera) of the Weddell Sea

    Science.gov (United States)

    Janussen, Dorte; Tabachnick, Konstantin R.; Tendal, Ole S.

    2004-07-01

    New Hexactinellida from the deep Weddel Sea are described. This moderately diverse hexactinellid fauna includes 14 species belonging to 12 genera, of which five species and one subgenus are new to science: Periphragella antarctica n. sp., Holascus pseudostellatus n. sp., Caulophacus (Caulophacus) discohexactinus n. sp., C. ( Caulodiscus) brandti n. sp., C. ( Oxydiscus) weddelli n. sp., and C. ( Oxydiscus) n. subgen. So far, 20 hexactinellid species have been reported from the deep Weddell Sea, 15 are known from the northern part and 10 only from here, while 10 came from the southern area, and five of these only from there. However, this apparent high "endemism" of Antarctic hexactinellid sponges is most likely the result of severe undersampling of the deep-sea fauna. We find no reason to believe that a division between an oceanic and a more continental group of species exists. The current poor database indicates that a substantial part of the deep hexactinellid fauna of the Weddell Sea is shared with other deep-sea regions, but it does not indicate a special biogeographic relationship with any other ocean.

  12. SeaWinds - Greenland

    Science.gov (United States)

    1999-01-01

    The frequent coverage provided by NASA's SeaWinds instrument on the QuikScat satellite provides unprecedented capability to monitor daily and seasonal changes in the key melt zones of Greenland, which is covered with a thick ice sheet that resulted from snow accumulating over tens of thousands of years. The thickness of the snow layers reveals details about the past global climate, and comparing snow accumulation and snow melting can provide insight into climate change and global warming. In particular, the extent of summer melting of snow in Greenland is considered a sensitive indicator of global change.Earlier scatterometer data has suggested that Greenland has experienced significantly more melting in recent years. This figure compares the melting observed over 15 days during July 1999 in Greenland. The red areas around the central blue and white areas are the main melt zones and have lower radar back scatter because of water on the surface that saturates the surface snow. As the days warm up, the melt extent dramatically increases. Comparing this data with computer models and past scatterometer data will help scientists evaluate the inter-annual variability of the melting as a step toward understanding potential climate change.The world's large ice sheets in Greenland and Antarctica act as vast storehouses of freshwater. Summer season melting releases large quantities of freshwater into the ocean, and year-to-year variations can have a significant impact on global sea level. Furthermore, long-term changes in the patterns and extent of melting on the large ice sheets reflect the effects of climate variability; thus Greenland is considered a sensitive indicator of global warming.Satellite microwave radars are extremely sensitive to melting and can provide the only effective means of accurately measuring the year-round picture of the extent and variability in ice sheet melting. Daily mean images were produced from QuikScat data collected over the Greenland ice

  13. Toxic Algae and Early Warning Management in Yellow Sea and Bohai Sea of China

    Institute of Scientific and Technical Information of China (English)

    Song; Lun; Song; Guangjun; Song; Yonggang; Xu; Xiaohong

    2014-01-01

    The research status of toxic algae in Yellow Sea and Bohai Sea are reviewed from the aspects of toxicity characteristics,toxic mechanism and early warning management,and the existing toxic algae and their toxicity in Yellow Sea and Bohai Sea are analyzed in the paper. The early warning level of toxic algae in Yellow Sea and Bohai Sea of China is put forward,and the research direction of shellfish poisoning in future is summarized.

  14. Integrating out the Dirac sea

    Energy Technology Data Exchange (ETDEWEB)

    Karbstein, Felix

    2009-07-08

    We introduce a new method for dealing with fermionic quantum field theories amenable to a mean-field-type approximation. In this work we focus on the relativistic Hartree approximation. Our aim is to integrate out the Dirac sea and derive a no-sea effective theory'' with positive energy single particle states only. As the derivation of the no-sea effective theory involves only standard Feynman diagrams, our approach is quite general and not restricted to particular space-time dimensions. We develop and illustrate the approach in the ''large N'' limit of the Gross-Neveu model family in 1+1 dimensions. As the Gross-Neveu model has been intensely studied and several analytical solutions are known for this model, it is an ideal testing ground for our no-sea effective theory approach. The chiral Gross-Neveu model, also referred to as 1+1 dimensional Nambu-Jona-Lasinio model, turns out to be of particular interest. In this case, we explicitly derive a consistent effective theory featuring both elementary ''{pi} meson'' fields and (positive energy) ''quark'' fields, starting from a purely fermionic quantum field theory. In the second part of this work, we apply our approach to the Walecka model in 1+1 and 3+1 dimensions. As the Dirac sea caused considerable difficulties in attempts to base nuclear physics on field theoretic models like the Walecka model, mean-field calculations were typically done without the sea. We confront several of these mean-field theory results with our no-sea effective theory approach. The potential of our approach is twofold. While the no-sea effective theory can be utilized to provide new analytical insights in particular parameter regimes, it also sheds new light on more fundamental issues as the explicit emergence of effective, Dirac-sea induced multi-fermion interactions in an effective theory with positive energy states only. (orig.)

  15. Sea Ice Concentration and Extent

    Science.gov (United States)

    Comiso, Josefino C.

    2014-01-01

    Among the most seasonal and most dynamic parameters on the surface of the Earth is sea ice which at any one time covers about 3-6% of the planet. In the Northern Hemisphere, sea ice grows in extent from about 6 x 10(exp 6) sq km to 16 x 10(exp 6) sq km, while in the Southern Hemisphere, it grows from about 3 x 10(exp 6) sq km to about 19 x 10(exp 6) sq km (Comiso, 2010; Gloersen et al., 1992). Sea ice is up to about 2-3 m thick in the Northern Hemisphere and about 1 m thick in the Southern Hemisphere (Wadhams, 2002), and compared to the average ocean depth of about 3 km, it is a relatively thin, fragile sheet that can break due to waves and winds or melt due to upwelling of warm water. Being constantly advected by winds, waves, and currents, sea ice is very dynamic and usually follows the directions of the many gyres in the polar regions. Despite its vast expanse, the sea ice cover was previously left largely unstudied and it was only in recent years that we have understood its true impact and significance as related to the Earths climate, the oceans, and marine life.

  16. Iodine emissions from the sea ice of the Weddell Sea

    Directory of Open Access Journals (Sweden)

    H. M. Atkinson

    2012-05-01

    Full Text Available Iodine compounds were measured above, below and within the sea ice of the Weddell Sea during a cruise in 2009, to elucidate the mechanism of local enhancement and volatilisation of iodine. I2 mixing ratios of up to 12.4 pptv were measured 10 m above the sea ice, and up to 31 pptv was observed above surface snow on the nearby Brunt Ice Shelf – large amounts. Atmospheric IO of up to 7 pptv was measured from the ship, and the average sum of HOI and ICl was 1.9 pptv. These measurements confirm the Weddell Sea as an iodine hotspot. Average atmospheric concentrations of CH3I, C2H5I, CH2ICl, 2-C3H7I, CH2IBr and 1-C3H7I were each 0.2 pptv or less. On the Brunt Ice Shelf, enhanced concentrations of CH3I and C2H5I (up to 0.5 and 1 pptv, respectively were observed in firn air, with a diurnal profile that suggests the snow may be a source. In the sea ice brine, iodocarbons concentrations were over 10 times those of the sea water below. The sum of iodide + iodate was depleted in sea ice samples, suggesting some missing iodine chemistry. Flux calculations suggest I2 dominates the iodine atom flux to the atmosphere, but models cannot reconcile the observations and suggest either a missing iodine source or other deficiencies in our understanding of iodine chemistry. The observation of new particle formation, consistent with the model predictions, strongly suggests an iodine source. This combined study of iodine compounds is the first of its kind in this unique region of sea ice rich in biology and rich in iodine chemistry.

  17. Iodine emissions from the sea ice of the Weddell Sea

    Directory of Open Access Journals (Sweden)

    H. M. Atkinson

    2012-11-01

    Full Text Available Iodine compounds were measured above, below and within the sea ice of the Weddell Sea during a cruise in 2009, to make progress in elucidating the mechanism of local enhancement and volatilisation of iodine. I2 mixing ratios of up to 12.4 pptv were measured 10 m above the sea ice, and up to 31 pptv was observed above surface snow on the nearby Brunt Ice Shelf – large amounts. Atmospheric IO of up to 7 pptv was measured from the ship, and the average sum of HOI and ICl was 1.9 pptv. These measurements confirm the Weddell Sea as an iodine hotspot. Average atmospheric concentrations of CH3I, C2H5I, CH2ICl, 2-C3H7I, CH2IBr and 1-C3H7I were each 0.2 pptv or less. On the Brunt Ice Shelf, enhanced concentrations of CH3I and C2H5I (up to 0.5 and 1 pptv respectively were observed in firn air, with a diurnal profile that suggests the snow may be a source. In the sea ice brine, iodocarbons concentrations were over 10 times those of the sea water below. The sum of iodide + iodate was depleted in sea ice samples, suggesting some missing iodine chemistry. Flux calculations suggest I2 dominates the iodine atom flux to the atmosphere, but models cannot reconcile the observations and suggest either a missing iodine source or other deficiencies in our understanding of iodine chemistry. The observation of new particle formation, consistent with the model predictions, strongly suggests an iodine source. This combined study of iodine compounds is the first of its kind in this unique region of sea ice rich in biology and rich in iodine chemistry.

  18. Alone by the Sea

    Directory of Open Access Journals (Sweden)

    Zoran Ferić

    2015-06-01

    Full Text Available 1.At first the island is just a sign on a yellow board with a drawing of a vessel and the letters saying “Car Ferry,” then it is a grayish silhouette in the blue of the sea, and then, later still, an acquaintance working on the ferry, who just nods briefly in greeting. Jablanac, ferry port, its pleasant lobby, and then, from the upper deck, a giant rock approaching. That is the object of a year-long desire: the moment of stepping off the boat and smelling the rosemary, diesel and sheep droppings, seeing the sharp rocks looking at the Strait of Senj, coarse limestone in sharp opposition to the signs that say: Benvenuti, Welcome, Willkommen!At home, on the terrace, in the shade of the oleander, there’s no wish to eat. Only swimming trunks are put on and then, barefoot, without a towel or sun-tanning lotion, off to the beach.“Why won’t you eat something?” grandma asks.She knows that there’s an exciting world waiting out there, but she knows nothing of the details. All friends went on a boat trip. And suddenly one step from the shade of a path covered with oleanders and acacias leads into the burning sun of the afternoon. The light screams, just like children in the water, just like white objects that radiate as if there are some powerful light bulbs within. The feeling of freedom of someone who has just arrived in a foreign place and can now do anything. There’s no one familiar on the beach, they all got in the boat and left. The seafront leading to the camp is full of people, naked children with dirty faces licking ice cream, young families pushing strollers, groups of teenagers who have just woken up from their last night’s party. But there’s no one that must be greeted. The feeling of freedom that’s at the same time close to death. Suddenly, all paths are open. That there are no obligations or friends waiting, this afternoon, until they come back, is a complete boon.

  19. Monitoring sea level and sea surface temperature trends from ERS satellites

    DEFF Research Database (Denmark)

    Andersen, Ole Baltazar; Knudsen, Per; Beckley, B.

    2002-01-01

    radiometer (AV-HRR) sea surface temperature observations. Global averaged spatial correlations between the 50degrees parallels are 0.87 between the ATSR and AVHRR based sea surface temperature trends-values, and 0.85 between the UP and ERS altimetric sea level trends. The spatial correlation between the ERS......Data from the two ESA satellites ERS-1 and ERS-2 are used in global and regional analysis of sea level and sea surface temperature trends over the last, 7.8 years. T he ERS satellites and in the future the ENVISAT satellite provide unique opportunity for monitoring both changes in sea level and sea...... surface temperature as these satellites are equipped with an altimeter to measure sea level height as well as an along track scanning radiometer (ATSR) to measure the sea surface temperature. Consistent increase in both sea level and sea surface temperatures are found in most parts of the Atlantic Ocean...

  20. Oil and the Caspian Sea

    International Nuclear Information System (INIS)

    Caspian Sea is the biggest lake in the world. It is almost F-shape and located between five Countries of Iran, Turkmenistan, Russia, Azarbayjohn, Ghazaghestan. Un fortunately, in the different region of the sea there are highly contaminated oil, in addition with other source of pollutants such as: agricultural, industrial and domestic pollution, which causes to eliminate the natural habitats of aquatic life and thus, the Caspian sea with all of the valuable natural sources of foods and energy is close to be destroyed. This paper studies the pollution by oil industry which causes the elimination of aquatic life and natural ecosystem, as well as, necessary plan to over come the present situation

  1. Radioactivity in the North Sea

    International Nuclear Information System (INIS)

    This chapter lists the main sources of radioactivity in the North Sea and explains the units used. The main source is naturally occuring long-lived radionuclides. Other significant sources are the Sellafield reprocessing plant, atmospheric atomic weapons testing, fallout from the Chernobyl reactor accident, the French nuclear reprocessing plant at Cap la Hague and oilfield production water brines. However, currently these are not significant compared with the natural background. If this is to continue, lower levels of discharge into the sea, strict control of new discharges and the cessation of atmospheric nuclear tests will be needed. There is a map showing the concentration of Cs137 in filtered water from the North Sea in 1985. (UK)

  2. GHRSST Level 4 DMI_OI North Sea and Baltic Sea Regional Foundation Sea Surface Temperature Analysis (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis by the Danish...

  3. Assimilation of sea surface temperature, sea ice concentration and sea ice drift in a model of the Southern Ocean

    OpenAIRE

    Barth, Alexander; Canter, Martin; Van Schaeybroeck, Bert; Vannitsem, Stéphane; Massonnet, François; Zunz, Violette; Mathiot, Pierre; Alvera Azcarate, Aïda; Beckers, Jean-Marie

    2015-01-01

    Current ocean models have relatively large errors and biases in the Southern Ocean. The aim of this study is to provide a reanalysis from 1985 to 2006 assimilating sea surface temperature, sea ice concentration and sea ice drift. In the following it is also shown how surface winds in the Southern Ocean can be improved using sea ice drift estimated from infrared radiometers. Such satellite observations are available since the late seventies and have the potential to improve the wind forcing be...

  4. Fluctuation of dominant mesozooplankton species in the Black Sea, North Sea and the Baltic Sea: Is a general trend recognisable?

    OpenAIRE

    NIERMANN, Ulrich; BİNGEL, Ferit; ERGÜN, Güner

    1998-01-01

    The distribution and fluctation of dominant pelagic species>300µ(Copepoda, Chaetognatha, Scyhozoa, Ctenophora and ichthyoplankton) of the southern Black Sea were compared with that of dominant species of the North Sea and the Baltic Sea in relation to oceanographic and environmental features. In all three seas, similar changes in the zooplankton composition took place at the end of the 1980's, and the beginning of the 1990's. - decreasing or increasing abundances of certain s...

  5. Climate change challenges for SEA

    DEFF Research Database (Denmark)

    Larsen, Sanne Vammen

    This paper takes a theoretical perspective on the challenges that climate changes pose for SEA. The theoretical framework used is the sociologist Ulrich Beck’s theory of risk society and the aspects that characterise this society. Climate change is viewed as a risk, and the theory is used to derive...... two challenges for the practice of SEA: delivering assessments and predictions; and handling differences in opinion and debate. Based on empirical evidence from document studies and interviews, the paper discusses the reflection of these theoretical challenges in practice....

  6. On The Black Sea Surozhian

    Science.gov (United States)

    Caraivan, Glicherie; Corneliu, Cerchia

    2016-04-01

    Some Black Sea researchers still support the idea of no other connection to the Mediterranean Sea between LGM and Karangatian Stage (Riss - Wurm). We try to clarify the source of these disagreements. C14 AMS age data (HERAS Project) made on undisturbed samples from a new Mamaia drilling hole where compared with the classical Black Sea stratigraphic schemes. A first transgressive event (Zone D) is found between 38.00 - 20.20 m depth. Zone D4 shows a fairly rapid rise of sea level, about 10 m below the present one indicating an inner shelf marine polyhaline environment. AMS age data show 14C ages between 53690 - 47359 y (MIS 1), corresponding to the "Surozhian Beds" of Popov. The "beach rock" from Zone E marks the decrease of the sea level after the maximum reached in Zone D4. Zone E mollusc shells AMS data, indicate 14C ages of 48724 - 44604 y, suggesting a long-time reworked material from the previous D4 zone sediments, and represents the beginning of the "regressive Tarkankutian" sequence.The Last Glacial Maximum (LGM) led to the retreat of the sea level down to about 100 m below the current one (27-17 ky BP), followed by an retreat of the shoreline to the present position. At the beginning of the Holocene - MIS 1 (8408-8132 cal. y BP), Black Sea brackish water level grew rapidly, up to -14 m below the present one (Zone F: 22, 57-20, 20 m). Zone F deposits could be correlated with the Bugazian strata. Then, a continuous rising of the Black Sea level is recorded up to a maximum of -2 m under the present one, about 6789 - 7063 cal. y BP, when a transgressive spurt ("Neolithic transgression") may have taken place. After that, given a weak Danubian sedimentary input, coastal erosion intensified. The coarse sandy sediments were reworked and pushed over the previous peat deposits, and suggest a classical "sedimentary regression", not a sea-level decrease. During the last 1.5 ky, sea level has risen towards the current one. Previous C14 dates from "Karangatian

  7. Sailing In Sea of Commerce

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The law of big fish swallowing little fish has expired when it comes to the era of new economy.What prevails nowadays in the sea of commerce is quick fish swallowing slow fish.In the Internet economy,small companies are not destined to lose to giants,but slow ones are doomed to become prey of their quick counterparts. The swiftly rising Yongkang Group has made a breakthrough in dental treatment by translating the law into practice.It is called"Law of the Sea."‘Law of the Sea’

  8. The politics of SEA indicators

    DEFF Research Database (Denmark)

    Gao, Jingjing; Kørnøv, Lone; Christensen, Per

    2013-01-01

    The use of indicators is not only technical and science-led, but also a value-laden social process, and thus concerns public participation, political judgment and decision-making. This article approaches the Chinese SEA indicator system from a science-policy interface and aims at: 1) contributing...... to the general recognition of indicators functioning at science-policy interfaces in SEA, and 2) analysing, through a Chinese case-study, to what extent national guidelines mediate the science-policy interaction. The overall finding is a strong emphasis on technical/science aspects found in the...

  9. How SEA can inform lenders

    DEFF Research Database (Denmark)

    Banhalmi-Zakar, Zsuzsa; Larsen, Sanne Vammen

    SEA can be a powerful tool to improve decision-making for plans, policies and programmes, but it can also be a useful for banks. SEA can help lenders address the reputational risks they are exposed to through financing projects that may have a negative impact on the environment and it can also help...... with identifying the financial incentives that ‘green’ projects attract. Although bank lending decisions apply to projects, examination of the lending practices of an Australian and a Hungarian bank have shown that decisions about the type of projects to target or avoid are also made at strategic level...

  10. 16 MW under the seas

    International Nuclear Information System (INIS)

    This article presents the Nemo project (Nemo stands for New Energy for Martinique and Overseas) and its precursor project, Ner 300, developed in cooperation between Akuo Energy and DCNS, and which is financed by the European Bank for Investment. These projects aim at exploiting sea thermal energy. Ner 300 will exploit the 20 degree difference between surface waters (25 C) and deep waters (5 C at 1.000 m under sea level). The article evokes works performed by DCNS to develop a prototype near the Reunion Island. The principle and operation are briefly described, and technological challenges are outlined

  11. Black Sea coastal forecasting system

    Directory of Open Access Journals (Sweden)

    A. I. Kubryakov

    2012-03-01

    Full Text Available The Black Sea coastal nowcasting and forecasting system was built within the framework of EU FP6 ECOOP (European COastalshelf sea OPerational observing and forecasting system project for five regions: the south-western basin along the coasts of Bulgaria and Turkey, the north-western shelf along the Romanian and Ukrainian coasts, coastal zone around of the Crimea peninsula, the north-eastern Russian coastal zone and the coastal zone of Georgia. The system operates in the real-time mode during the ECOOP project and afterwards. The forecasts include temperature, salinity and current velocity fields. Ecosystem model operates in the off-line mode near the Crimea coast.

  12. Quarterly Fishery Surveys - Salton Sea [ds428

    Data.gov (United States)

    California Department of Resources — In the spring of 2003, California Department of Fish and Game (CDFG) personnel began quarterly sampling of Salton Sea fish at fourteen stations around the sea, as...

  13. OW NASA SeaWIFS Ocean Color

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The dataset contains satellite-derived sea-surface ocean color (chlorophyll-a) measurements collected by means of the Sea-viewing Wide Field-of-view Sensor...

  14. Global and Regional Sea Level Change

    OpenAIRE

    Wenzel, Manfred; Schröter, Jens

    2012-01-01

    Sea level variations prior to the launch of satellite altimeters are estimated by analysing historic tide gauge records. Recently, a number of groups have reconstructed sea level by applying EOF techniques to gappy data. We complement this study with alternativemethods. In a first step gaps in 178 records of sea level change are filled using the pattern recognition capabilities of artificial neural networks. Afterwards satellite altimetry is used to extrapolate local sea level change to globa...

  15. Global Warming and Caspian Sea Level Fluctuations

    OpenAIRE

    Ardakanian, Reza; Alemohammad, Seyed Hamed

    2013-01-01

    Coastal regions have a high social, economical and environmental importance. Due to this importance the sea level fluctuations can have many bad consequences. In this research the correlation between the increasing trend of temperature in coastal stations due to Global Warming and the Caspian Sea level has been established. The Caspian Sea level data has been received from the Jason-1 satellite. It was resulted that the monthly correlation between the temperature and sea level is high and als...

  16. A survey of European sea level infrastructure

    OpenAIRE

    Woodworth, P. L.; Rickards, L. J.; Pérez, B

    2009-01-01

    This paper summaries findings from a survey of European sea level infrastructure (tide gauges, telemetry methods, ancillary information) conducted at the end of 2008 on behalf of the Tsunami Risk ANd Strategies For the European Region (TRANSFER), Tsunami Early Warning and Mitigation System in the North-Eastern Atlantic, the Mediterranean and Connected Seas (NEAMTWS), European Sea Level Service (ESEAS) and Global Sea Level Observing System (GLOSS) projects and programmes. Approximately 478 str...

  17. Characteristics of Environment in Yatsushiro Sea

    OpenAIRE

    Takikawa, Kiyoshi; Aoyama, Chiharu; TANAKA Kenji; Morimoto, Kentaro; Watanabe, Kaname; タキカワ, キヨシ; アオヤマ, チハル; タナカ, ケンジ; モリモト, ケンタロウ; ワタナベ, カナメ; 滝川, 清; 青山, 千春; 田中, 健路; 森本, 剣太郎

    2005-01-01

    The Yatsushiro Sea has serious environmental problems similar to those affecting the Ariake Sea. In this study we performed a causal analysis of environmental change in the Yatsushiro Sea by investigating environmental characteristics such as water quality and atmospheric phenomena over the past 26 years. Numerical experiments yielded the following results: 1) there exist 5 distinct environmental domains within the Yatsushiro Sea, 2) during summer, density layers develop over the entire Yatsu...

  18. 33 CFR 2.22 - Territorial sea.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Territorial sea. 2.22 Section 2... Jurisdictional Terms § 2.22 Territorial sea. (a) With respect to the United States, the following apply— (1) Territorial sea means the waters, 12 nautical miles wide, adjacent to the coast of the United States...

  19. Messinian events in the Black Sea

    NARCIS (Netherlands)

    van Baak, Christiaan G C; Radionova, Eleanora P.; Golovina, Larisa A.; Raffi, Isabella; Kuiper, Klaudia F.; Vasiliev, Iuliana; Krijgsman, Wout

    2015-01-01

    Past hydrological interactions between the Mediterranean Sea and Black Sea are poorly resolved due to complications in establishing a high-resolution time frame for the Black Sea. We present a new greigite-based magnetostratigraphic age model for the Mio-Pliocene deposits of DSDP Hole 380/380A, dril

  20. OIL POLLUTION OF THE BLACK SEA

    Directory of Open Access Journals (Sweden)

    Georgiy Biliavskiy

    2012-09-01

    Full Text Available  Article is devoted to meaningfulness estimation of some factors in forming ecological conditions in regions of the Black Sea. Comparative estimation of anthropogenic contamination degree of sea regions environment considered. The zons the most unhappy in ecological attitude are defined, that allows to mark first and foremost arrangements on improvement of ecological situation of the Black Sea.

  1. Generic Hurricane Extreme Seas State

    DEFF Research Database (Denmark)

    Wehmeyer, Christof; Skourup, Jesper; Frigaard, Peter

    2012-01-01

    hurricane generates seas by Young (1998, 2003, and 2006), requiring maximum wind speeds, forward velocity and radius to maximum wind speed. An averaged radius to maximum sustained wind speeds, according to Hsu et al. (1998) and averaged forward speed of cyclonic storms are applied in the initial state. In a...

  2. The sea urchin immune system

    Directory of Open Access Journals (Sweden)

    LC Smith

    2006-05-01

    Full Text Available Metchnikoff’s use of sea star larvae to observe encapsulation and phagocytosis, which was followedmuch later by allograft rejection kinetics, revealed that echinoderms had an innate immune system thatwas lacking of adaptive attributes. Larval sea urchins mount defenses in response to contact withmicrobes, which are mediated by phagocytic blastocoelar cells and pigment cells. In the adult, thecoelomocytes mediate immune responses through phagocytosis and encapsulation of foreign particles inaddition to degranulation of antimicrobial molecules. Molecular analysis of immune functions in the seaurchin has demonstrated a complement system that appears to have multiple alternative pathways andseveral activators of the lectin pathway, but may be missing the terminal pathway. Other genes andproteins involved in the sea urchin immunity include expanded sets of lectins, proteins with scavengerreceptor cysteine-rich repeats, Toll-like receptors and associated signalling proteins. A vast array ofproteins belonging to the 185/333 family are expressed in coelomocytes in response to lipopolysaccharideand show a surprising level of diversity. The sea urchin innate immune system has a number of largegene families with unexpected complexities and elevated levels of diversification.

  3. The Sea Ice Board Game

    Science.gov (United States)

    Bertram, Kathryn Berry

    2008-01-01

    The National Science Foundation-funded Arctic Climate Modeling Program (ACMP) provides "curriculum resource-based professional development" materials that combine current science information with practical classroom instruction embedded with "best practice" techniques for teaching science to diverse students. The Sea Ice Board Game, described…

  4. Killer storms from the seas

    Digital Repository Service at National Institute of Oceanography (India)

    Varkey, M.J.

    The author has discussed the distruction taking place due to cyclone in the Indian subcontinent of formation which is said to be the result of thermal fronts in the atmosphere and sea interaction of different air masses is discussed in detailed...

  5. Past and present Aral Sea

    Science.gov (United States)

    Dukhovniy, Viktor; Stulina, Galina; Eshchanov, Odylbek

    2013-04-01

    The tragedy of disappearing of Aral Sea is well known to the World. Before and after collapse of Soviet Union, a huge quantity of scientific and popular editions described with grief the situation around the Aral Sea. After the NIS states became independent, World Bank, UNDP, UNEP in proper competition with each other had provided some assessment of the situation through presentation of some small and medium grants, but after 2000, the local population remained alone with own problems. Although on the eyes of the present generation a unique transformation of great water body into deserts took place, the global scientific community did not find forces and financing for real and detail investigation of the processes accompanying the Sea shrinking and land formation. We should acknowledge and give big respect to NATO, later to German Government that through GTZ (now GIZ) - German International Collaboration Agency - and GFZ (Potzdam) paid attention to this area of environment crisis and organized scientific and protective design in the so-called Priaralie - the territory around the drying Sea and delta of the two rivers - Amudarya and Syrdarya. Thank to this assistance, the local specialists in collaboration with limited a number of foreign scientists (N.Aladin, P.Zavialov, Joop de Schutter, Hans Wilps, Hedi Oberhansli) organized significant works for detail socioeconomic, ecological and hydrological assessment situation in Priaralie and on the Aral sea coast. On this base, Ministry of Agriculture and Water resources of Uzbekistan and State Committee of Water resources of Kazakhstan developed a plan of rehabilitation of Amudarya and Syrdarya deltas and started implementation of these projects. If Kazakh water authority moved ahead in wetland restoration faster, a forestation of delta and drying bed of Aral Sea got big success in Uzbek territory. 244 thousands hectares of saxsaul and tamarix were planted for protection of the Priaralie. By request of GTZ SIC, ICWC

  6. Management of the Wadden Sea

    Science.gov (United States)

    Wolff, W. J.; Zijlstra, J. J.

    1980-03-01

    The Wadden Sea situated along the North Sea coasts of Denmark, the Federal Republic of Germany and The Netherlands represents one of the world's largest bar-built type of estuaries. The area is a typical sedimentation and mineralization basin, with a large influx of organic matter from the adjoining North Sea, consequently a delicate oxygen balance and a rich benthic macrofauna, poor in species, which serves as food for juveniles of some commercially important North Sea fishes and for large numbers of migrating and wintering waders and waterfowl. Past and present activities of the human society in the area include fisheries (mainly for shrimp and mussels, semi-culture), shipping, land reclamation, recreation, dredging for sand and shells, and waste discharge from industries and human communities. Until the present these activities, although sometimes conflicting, did not fundamentally affect the area and its biota (pollution excluded), but future claims, including the construction of large deep-sea harbours, drilling for natural gas and oil, large-scale land reclamation and increased industrialization etc., might gradually induce degradation. For instance, area reduction by continued land reclamation could lead to irreversible losses of specific biotopes (e. g. salt-marshes, mud-flats), which could affect the size of bird and fish populations in a much wider region. Increased pollution, which has already inflicted damage on bird and seal populations, could reduce the fauna and hence the value of the area as a natural sanctuary. In the event of a proposal for a new human activity in the area, the present standing practice in the countries concerned requires an evaluation of its safety and economic aspects and its environmental impact. However, the various plans are considered separately and there is a general need for integrated management of the area.

  7. Sea ice variability and trends in the Weddell Sea for 1979-2006

    OpenAIRE

    Schwegmann, Sandra; Timmermann, Ralph; Gerdes, Rüdiger; Lemke, Peter

    2012-01-01

    Sea ice concentration in the Weddell Sea is subject to regional climate variability. The magnitude and origin of local trends in the sea ice coverage were studied using the bootstrap algorithm sea ice concentration data from the NSIDC for 1979-2006. The impact of atmospheric forcing such as air temperature, wind speed, and cloud coverage, gained from NCEP/NCAR reanalysis, on sea ice was assessed by analyzing correlation coefficients between the respective atmospheric component and the satelli...

  8. Sea-level variability in the Caribbean Sea over the last century

    OpenAIRE

    Torres Parra, R. Ricardo

    2013-01-01

    Mean sea level rise exposes coasts to increasing risks. For the Caribbean Sea, the regional and local sea-level behaviour is not well known. This study has investigated the sea level behavior in the region at different frequencies during the last century, to provide updated, accurate and useful information to implement coastal adaptation responses to sea-level hazards. Time series from 28 tide-gauges, 18 years of altimetry and various atmospheric and oceanographic climatologies have been used...

  9. Distribution characteristics of marine litter on the sea bed of the East China Sea and the South Sea of Korea

    Science.gov (United States)

    Lee, Dae-In; Cho, Hyeon-Seo; Jeong, Sun-Beom

    2006-10-01

    The types, quantities, and distribution of marine litter found on the sea bed of the East China Sea and the South Sea of Korea are surveyed. Surveys were evaluated using bottom trawl nets during 1996-2005 cruises. Mean distribution densities were high in coastal seas, especially in the South Sea of Korea offshore from Yeosu, with 109.8 kg km -2, and low in the East China Sea, with densities of 30.6 kg km -2. Fishing gear, such as pots, nets, octopus jars, and fishing lines, accounted for about 42-72% and 37-62% of litter items in the East China Sea and the South Sea of Korea, respectively, whereas the contributions of rubber, vinyl, metal, plastic, glass, wood, and clothing were below 30% mainly. Rope and drum composition fluctuated greatly, between 54% and 0%. Eel and net pots dominated the marine debris of the South Sea of Korea, and some vinyl, plastics, and fishing gear made in Korea, China, and Japan were collected in abundance in the East China Sea. Fishing gear was probably discarded into the sea, deliberately or inadvertently, by fishing operations. A comprehensive joint approach by Korea, China, and Japan is needed for the continuous monitoring of input sources, the actual conditions, and the behavior of marine litter for protection against litter pollution and fisheries resource management in this area.

  10. Temperature, Salinity, Oxygen, Phosphate, pH and Alkalinity data collected in the North Atlantic Ocean, Baltic Sea, Barents Sea, Greenland Sea, North Sea, Norwegian Sea and White Sea from R/Vs Artemovsk, Atlantida, Okeanograf, Professor Rudovits, and ice observations, 1957 - 1995 (NODC Accession 0073674)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature, Salinity, Oxygen, Phosphate, pH and Alkalinity data collected in the North Atlantic Ocean, Baltic Sea, Barents Sea, Greenland Sea, North Sea, Norwegian...

  11. Evaluation of the sea ice proxy IP25 against observational and diatom proxy data in the SW Labrador Sea

    DEFF Research Database (Denmark)

    Weckstrom, Kaarina; Masse, Guillaume; Collins, Lewis G.; Hanhijarvi, Sami; Bouloubassi, Ioanna; Sicre, Marie-Alexandrine; Seidenkrantz, Marit-Solveig; Schmidt, Sabine; Andersen, Thorbjorn J.; Andersen, Morten L.; Hill, Brian; Kuijpers, Antoon

    , identified in marine sediments underlying seasonal sea ice, has emerged as a potential sea ice specific proxy for past sea ice cover. We tested the reliability of this biomarker as a sea ice proxy against observational sea ice data (sea ice concentrations from the global HadISST1 database) and against a more...

  12. Seasonal variability in the Baltic Sea level

    OpenAIRE

    Marek Świrgoń; Małgorzata Stramska; Halina Kowalewska-Kalkowska

    2013-01-01

    Sea level is subject to spatial and temporal variability on different scales. In this paper we investigate seasonal variability in the open Baltic Sea level using daily satellite altimetry data for the period 1 January 1993-31 December 2010. Our results indicate that there is a well-pronounced seasonal cycle in the 18-year average sea level and in its standard deviation. The average annual SLA amplitude in the open Baltic Sea is about 18 cm. The seasonal cycle of the SLA in the Baltic Sea is ...

  13. Regional Variability in Sea Level Rise

    OpenAIRE

    Meyssignac, Benoit

    2012-01-01

    Over the XXth century, tide gauge records indicate a rise in global sea level of 1.7 mm.a-1. For the past two decades, satellite altimetry data indicate a faster sea level rise of 3.2 mm.a-1 (period 1993-2011). Thanks to its global coverage, they also reveal a strong regional variability in sea level rise that is several times bigger than the global rise in many regions of the world. This regional signal, which must be added to the global sea level rise to compute the total sea level signal, ...

  14. Global Warming and Caspian Sea Level Fluctuations

    CERN Document Server

    Ardakanian, Reza

    2013-01-01

    Coastal regions have a high social, economical and environmental importance. Due to this importance the sea level fluctuations can have many bad consequences. In this research the correlation between the increasing trend of temperature in coastal stations due to Global Warming and the Caspian Sea level has been established. The Caspian Sea level data has been received from the Jason-1 satellite. It was resulted that the monthly correlation between the temperature and sea level is high and also positive and almost the same for all the stations. But the yearly correlation was negative. It means that the sea level has decreased by the increase in temperature.

  15. Contribution à l'étude géologique des granitoïdes de Vallorcine, Beaufort, Lauzière, de leur encaissant et des minéralisations uranifères associées. Alpes Françaises.

    OpenAIRE

    Poncerry, Eddie

    1981-01-01

    Cette étude porte sur trois secteurs des massifs cristallins externes des Alpes Françaises: les secteurs de Vallorcine(massif des Aiguilles Rouges),de Beaufort et de la Lauzière (massif de Belledonne). Ils présentent tous trois la particularité de renfermer des indices d'uranium,en liaison au moins spatiale avec des intrusions granitiques. Aussi le problèmedes granitisations a-t'il constitué le fil directeur de cette étude, méme sileur rôle s 'est révélé moins important que prévu pour la form...

  16. Clearing of the sea bed in the North Sea 1993

    International Nuclear Information System (INIS)

    The report relates to an NPD (Norwegian Petroleum Directorate) project which aimed to clear away objects from the sea bed on the Norwegian continental shelf. The project was divided in two phases. Phase 1 included the recording of objects by the use of sonars, and phase 2 covered the clearing operation itself. The results from the project, which included a fishery-intensive and oil-related area of 1300 km2 on Egersundbanken, are presented. 3 figs., 4 tabs

  17. Sea ice density estimation in the Bohai Sea using the hyperspectral remote sensing technology

    Science.gov (United States)

    Liu, Chengyu; Shao, Honglan; Xie, Feng; Wang, Jianyu

    2014-11-01

    Sea ice density is one of the significant physical properties of sea ice and the input parameters in the estimation of the engineering mechanical strength and aerodynamic drag coefficients; also it is an important indicator of the ice age. The sea ice in the Bohai Sea is a solid, liquid and gas-phase mixture composed of pure ice, brine pockets and bubbles, the density of which is mainly affected by the amount of brine pockets and bubbles. The more the contained brine pockets, the greater the sea ice density; the more the contained bubbles, the smaller the sea ice density. The reflectance spectrum in 350~2500 nm and density of sea ice of different thickness and ages were measured in the Liaodong Bay of the Bohai Sea during the glacial maximum in the winter of 2012-2013. According to the measured sea ice density and reflectance spectrum, the characteristic bands that can reflect the sea ice density variation were found, and the sea ice density spectrum index (SIDSI) of the sea ice in the Bohai Sea was constructed. The inversion model of sea ice density in the Bohai Sea which refers to the layer from surface to the depth of penetration by the light was proposed at last. The sea ice density in the Bohai Sea was estimated using the proposed model from Hyperion image which is a hyperspectral image. The results show that the error of the sea ice density inversion model is about 0.0004 g•cm-3. The sea ice density can be estimated through hyperspectral remote sensing images, which provide the data support to the related marine science research and application.

  18. Catfish - King of the sea

    OpenAIRE

    Godø, Olav Rune; Huse, Irene; Michalsen, Kathrine

    1995-01-01

    During an acoustic tagging experiment on cod in the Barents Sea in March 1995 a hierarchy between different fish species was revealed, and the catfish (Anarhichas sp.) was observed to be dominant in relation to cod and haddock. When catfish are present at the fishing grounds, the dominant feeding behaviour of this species might reduce efficiency on other species. If longline catch data are used for stock assessment purposes, the catfish population might therefore be overestimat...

  19. Sea sand for reactive barriers

    International Nuclear Information System (INIS)

    Some phosphates have the property to suck in radioactive metals in solution, what it is taken in advance to make reactive barriers which are placed in the nuclear waste repositories. In an effort for contributing to the study of this type of materials, it has been obtained the zirconium silicate (ZrSiO4) and the alpha zirconium hydrogen phosphate (Zr(HPO4) 2H2O) starting from sea sand in an easy and economic way. (Author)

  20. Ploughing the deep sea floor

    OpenAIRE

    Puig, Pere; Canals, Miquel; Company, Joan B.; Martín, Jacobo; Amblas, David; Lastras, Galderic; Palanques, Albert; Calafat, Antoni M.

    2012-01-01

    Bottom trawling is a non-selective commercial fishing technique whereby heavy nets and gear are pulled along the sea floor. The direct impact of this technique on fish populations1, 2 and benthic communities3, 4 has received much attention, but trawling can also modify the physical properties of seafloor sediments, water–sediment chemical exchanges and sediment fluxes5, 6. Most of the studies addressing the physical disturbances of trawl gear on the seabed have been undertaken in coastal and ...